diff --git a/.eslintrc.js b/.eslintrc.js
index e0313aad16976..0d71fd0a99f77 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -17,9 +17,6 @@
  * under the License.
  */
 
-const { readdirSync } = require('fs');
-const { resolve } = require('path');
-
 const APACHE_2_0_LICENSE_HEADER = `
 /*
  * Licensed to Elasticsearch B.V. under one or more contributor
@@ -294,7 +291,7 @@ module.exports = {
               },
               {
                 target: [
-                  '(src|x-pack)/legacy/**/*',
+                  'src/legacy/**/*',
                   '(src|x-pack)/plugins/**/(public|server)/**/*',
                   'examples/**/*',
                 ],
@@ -325,14 +322,11 @@ module.exports = {
               },
               {
                 target: [
-                  '(src|x-pack)/legacy/**/*',
+                  'src/legacy/**/*',
                   '(src|x-pack)/plugins/**/(public|server)/**/*',
                   'examples/**/*',
                   '!(src|x-pack)/**/*.test.*',
                   '!(x-pack/)?test/**/*',
-                  // next folder contains legacy browser tests which can't be migrated to jest
-                  // which import np files
-                  '!src/legacy/core_plugins/kibana/public/__tests__/**/*',
                 ],
                 from: [
                   '(src|x-pack)/plugins/**/(public|server)/**/*',
@@ -347,14 +341,6 @@ module.exports = {
                   '(src|x-pack)/plugins/**/*',
                   '!(src|x-pack)/plugins/**/server/**/*',
 
-                  'src/legacy/core_plugins/**/*',
-                  '!src/legacy/core_plugins/**/server/**/*',
-                  '!src/legacy/core_plugins/**/index.{js,mjs,ts,tsx}',
-
-                  'x-pack/legacy/plugins/**/*',
-                  '!x-pack/legacy/plugins/**/server/**/*',
-                  '!x-pack/legacy/plugins/**/index.{js,mjs,ts,tsx}',
-
                   'examples/**/*',
                   '!examples/**/server/**/*',
                 ],
@@ -374,12 +360,7 @@ module.exports = {
               },
               {
                 target: ['src/core/**/*'],
-                from: [
-                  'plugins/**/*',
-                  'src/plugins/**/*',
-                  'src/legacy/core_plugins/**/*',
-                  'src/legacy/ui/**/*',
-                ],
+                from: ['plugins/**/*', 'src/plugins/**/*', 'src/legacy/ui/**/*'],
                 errorMessage: 'The core cannot depend on any plugins.',
               },
               {
@@ -392,12 +373,6 @@ module.exports = {
                 target: [
                   'test/plugin_functional/plugins/**/public/np_ready/**/*',
                   'test/plugin_functional/plugins/**/server/np_ready/**/*',
-                  'src/legacy/core_plugins/**/public/np_ready/**/*',
-                  'src/legacy/core_plugins/vis_type_*/public/**/*',
-                  '!src/legacy/core_plugins/vis_type_*/public/legacy*',
-                  'src/legacy/core_plugins/**/server/np_ready/**/*',
-                  'x-pack/legacy/plugins/**/public/np_ready/**/*',
-                  'x-pack/legacy/plugins/**/server/np_ready/**/*',
                 ],
                 allowSameFolder: true,
                 errorMessage:
@@ -447,22 +422,14 @@ module.exports = {
       settings: {
         // instructs import/no-extraneous-dependencies to treat certain modules
         // as core modules, even if they aren't listed in package.json
-        'import/core-modules': ['plugins', 'legacy/ui'],
+        'import/core-modules': ['plugins'],
 
         'import/resolver': {
           '@kbn/eslint-import-resolver-kibana': {
             forceNode: false,
             rootPackageName: 'kibana',
             kibanaPath: '.',
-            pluginMap: readdirSync(resolve(__dirname, 'x-pack/legacy/plugins')).reduce(
-              (acc, name) => {
-                if (!name.startsWith('_')) {
-                  acc[name] = `x-pack/legacy/plugins/${name}`;
-                }
-                return acc;
-              },
-              {}
-            ),
+            pluginMap: {},
           },
         },
       },
@@ -768,16 +735,6 @@ module.exports = {
       },
     },
 
-    /**
-     * GIS overrides
-     */
-    {
-      files: ['x-pack/legacy/plugins/maps/**/*.js'],
-      rules: {
-        'react/prefer-stateless-function': [0, { ignorePureComponents: false }],
-      },
-    },
-
     /**
      * ML overrides
      */
@@ -816,7 +773,7 @@ module.exports = {
     },
     {
       // typescript only for front and back end
-      files: ['x-pack/{,legacy/}plugins/security_solution/**/*.{ts,tsx}'],
+      files: ['x-pack/plugins/security_solution/**/*.{ts,tsx}'],
       rules: {
         // This will be turned on after bug fixes are complete
         // '@typescript-eslint/explicit-member-accessibility': 'warn',
@@ -862,7 +819,7 @@ module.exports = {
     // },
     {
       // typescript and javascript for front and back end
-      files: ['x-pack/{,legacy/}plugins/security_solution/**/*.{js,mjs,ts,tsx}'],
+      files: ['x-pack/plugins/security_solution/**/*.{js,mjs,ts,tsx}'],
       plugins: ['eslint-plugin-node', 'react'],
       env: {
         mocha: true,
@@ -1093,7 +1050,7 @@ module.exports = {
     {
       // typescript only for front and back end
       files: [
-        'x-pack/{,legacy/}plugins/{alerts,alerting_builtins,actions,task_manager,event_log}/**/*.{ts,tsx}',
+        'x-pack/plugins/{alerts,alerting_builtins,actions,task_manager,event_log}/**/*.{ts,tsx}',
       ],
       rules: {
         '@typescript-eslint/no-explicit-any': 'error',
@@ -1242,10 +1199,7 @@ module.exports = {
      * TSVB overrides
      */
     {
-      files: [
-        'src/plugins/vis_type_timeseries/**/*.{js,mjs,ts,tsx}',
-        'src/legacy/core_plugins/vis_type_timeseries/**/*.{js,mjs,ts,tsx}',
-      ],
+      files: ['src/plugins/vis_type_timeseries/**/*.{js,mjs,ts,tsx}'],
       rules: {
         'import/no-default-export': 'error',
       },
diff --git a/kibana.d.ts b/kibana.d.ts
index b707405ffbeaf..50f8b8690d944 100644
--- a/kibana.d.ts
+++ b/kibana.d.ts
@@ -28,7 +28,6 @@ export { Public, Server };
 /**
  * All exports from TS ambient definitions (where types are added for JS source in a .d.ts file).
  */
-import * as LegacyKibanaPluginSpec from './src/legacy/plugin_discovery/plugin_spec/plugin_spec_options';
 import * as LegacyKibanaServer from './src/legacy/server/kbn_server';
 
 /**
@@ -39,8 +38,4 @@ export namespace Legacy {
   export type Request = LegacyKibanaServer.Request;
   export type ResponseToolkit = LegacyKibanaServer.ResponseToolkit;
   export type Server = LegacyKibanaServer.Server;
-
-  export type InitPluginFunction = LegacyKibanaPluginSpec.InitPluginFunction;
-  export type UiExports = LegacyKibanaPluginSpec.UiExports;
-  export type PluginSpecOptions = LegacyKibanaPluginSpec.PluginSpecOptions;
 }
diff --git a/src/cli/serve/serve.js b/src/cli/serve/serve.js
index d8bd39b9dcdf4..a1715cf3dba2c 100644
--- a/src/cli/serve/serve.js
+++ b/src/cli/serve/serve.js
@@ -48,11 +48,6 @@ const CAN_CLUSTER = canRequire(CLUSTER_MANAGER_PATH);
 const REPL_PATH = resolve(__dirname, '../repl');
 const CAN_REPL = canRequire(REPL_PATH);
 
-// xpack is installed in both dev and the distributable, it's optional if
-// install is a link to the source, not an actual install
-const XPACK_DIR = resolve(__dirname, '../../../x-pack');
-const XPACK_INSTALLED = canRequire(XPACK_DIR);
-
 const pathCollector = function () {
   const paths = [];
   return function (path) {
@@ -137,16 +132,7 @@ function applyConfigOverrides(rawConfig, opts, extraCliOptions) {
   if (opts.logFile) set('logging.dest', opts.logFile);
 
   set('plugins.scanDirs', _.compact([].concat(get('plugins.scanDirs'), opts.pluginDir)));
-  set(
-    'plugins.paths',
-    _.compact(
-      [].concat(
-        get('plugins.paths'),
-        opts.pluginPath,
-        XPACK_INSTALLED && !opts.oss ? [XPACK_DIR] : []
-      )
-    )
-  );
+  set('plugins.paths', _.compact([].concat(get('plugins.paths'), opts.pluginPath)));
 
   merge(extraCliOptions);
   merge(readKeystore());
diff --git a/src/core/public/injected_metadata/injected_metadata_service.ts b/src/core/public/injected_metadata/injected_metadata_service.ts
index 5b51bc823d166..bd8c9e91f15a2 100644
--- a/src/core/public/injected_metadata/injected_metadata_service.ts
+++ b/src/core/public/injected_metadata/injected_metadata_service.ts
@@ -58,19 +58,6 @@ export interface InjectedMetadataParams {
     uiPlugins: InjectedPluginMetadata[];
     anonymousStatusPage: boolean;
     legacyMetadata: {
-      app: {
-        id: string;
-        title: string;
-      };
-      bundleId: string;
-      version: string;
-      branch: string;
-      buildNum: number;
-      buildSha: string;
-      basePath: string;
-      serverName: string;
-      devMode: boolean;
-      category?: AppCategory;
       uiSettings: {
         defaults: Record<string, UiSettingsParams>;
         user?: Record<string, UserProvidedValues>;
@@ -167,18 +154,6 @@ export interface InjectedMetadataSetup {
   getPlugins: () => InjectedPluginMetadata[];
   getAnonymousStatusPage: () => boolean;
   getLegacyMetadata: () => {
-    app: {
-      id: string;
-      title: string;
-    };
-    bundleId: string;
-    version: string;
-    branch: string;
-    buildNum: number;
-    buildSha: string;
-    basePath: string;
-    serverName: string;
-    devMode: boolean;
     uiSettings: {
       defaults: Record<string, UiSettingsParams>;
       user?: Record<string, UserProvidedValues> | undefined;
diff --git a/src/core/server/index.ts b/src/core/server/index.ts
index e136c699f7246..70ef93963c69f 100644
--- a/src/core/server/index.ts
+++ b/src/core/server/index.ts
@@ -339,14 +339,7 @@ export {
   SavedObjectsMigrationVersion,
 } from './types';
 
-export {
-  LegacyServiceSetupDeps,
-  LegacyServiceStartDeps,
-  LegacyServiceDiscoverPlugins,
-  LegacyConfig,
-  LegacyUiExports,
-  LegacyInternals,
-} from './legacy';
+export { LegacyServiceSetupDeps, LegacyServiceStartDeps, LegacyConfig } from './legacy';
 
 export {
   CoreStatus,
diff --git a/src/core/server/legacy/config/ensure_valid_configuration.test.ts b/src/core/server/legacy/config/ensure_valid_configuration.test.ts
index 702840b8a0a6a..700fe69954655 100644
--- a/src/core/server/legacy/config/ensure_valid_configuration.test.ts
+++ b/src/core/server/legacy/config/ensure_valid_configuration.test.ts
@@ -39,17 +39,12 @@ describe('ensureValidConfiguration', () => {
       configService as any,
       {
         settings: 'settings',
-        pluginSpecs: 'pluginSpecs',
-        disabledPluginSpecs: 'disabledPluginSpecs',
-        pluginExtendedConfig: 'pluginExtendedConfig',
-        uiExports: 'uiExports',
+        legacyConfig: 'pluginExtendedConfig',
       } as any
     );
     expect(getUnusedConfigKeys).toHaveBeenCalledTimes(1);
     expect(getUnusedConfigKeys).toHaveBeenCalledWith({
       coreHandledConfigPaths: ['core', 'elastic'],
-      pluginSpecs: 'pluginSpecs',
-      disabledPluginSpecs: 'disabledPluginSpecs',
       settings: 'settings',
       legacyConfig: 'pluginExtendedConfig',
     });
diff --git a/src/core/server/legacy/config/ensure_valid_configuration.ts b/src/core/server/legacy/config/ensure_valid_configuration.ts
index 5cd1603ea65fb..34f98b9b3a795 100644
--- a/src/core/server/legacy/config/ensure_valid_configuration.ts
+++ b/src/core/server/legacy/config/ensure_valid_configuration.ts
@@ -19,19 +19,17 @@
 
 import { getUnusedConfigKeys } from './get_unused_config_keys';
 import { ConfigService } from '../../config';
-import { LegacyServiceDiscoverPlugins } from '../types';
 import { CriticalError } from '../../errors';
+import { LegacyServiceSetupConfig } from '../types';
 
 export async function ensureValidConfiguration(
   configService: ConfigService,
-  { pluginSpecs, disabledPluginSpecs, pluginExtendedConfig, settings }: LegacyServiceDiscoverPlugins
+  { legacyConfig, settings }: LegacyServiceSetupConfig
 ) {
   const unusedConfigKeys = await getUnusedConfigKeys({
     coreHandledConfigPaths: await configService.getUsedPaths(),
-    pluginSpecs,
-    disabledPluginSpecs,
     settings,
-    legacyConfig: pluginExtendedConfig,
+    legacyConfig,
   });
 
   if (unusedConfigKeys.length > 0) {
diff --git a/src/core/server/legacy/config/get_unused_config_keys.test.ts b/src/core/server/legacy/config/get_unused_config_keys.test.ts
index f8506b5744030..6ce69fca0270a 100644
--- a/src/core/server/legacy/config/get_unused_config_keys.test.ts
+++ b/src/core/server/legacy/config/get_unused_config_keys.test.ts
@@ -17,7 +17,7 @@
  * under the License.
  */
 
-import { LegacyPluginSpec, LegacyConfig, LegacyVars } from '../types';
+import { LegacyConfig, LegacyVars } from '../types';
 import { getUnusedConfigKeys } from './get_unused_config_keys';
 
 describe('getUnusedConfigKeys', () => {
@@ -35,8 +35,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {},
           legacyConfig: getConfig(),
         })
@@ -47,8 +45,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {
             presentInBoth: true,
             alsoInBoth: 'someValue',
@@ -65,8 +61,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {
             presentInBoth: true,
           },
@@ -82,8 +76,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {
             presentInBoth: true,
             onlyInSetting: 'value',
@@ -99,8 +91,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {
             elasticsearch: {
               username: 'foo',
@@ -121,8 +111,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {
             env: 'development',
           },
@@ -139,8 +127,6 @@ describe('getUnusedConfigKeys', () => {
       expect(
         await getUnusedConfigKeys({
           coreHandledConfigPaths: [],
-          pluginSpecs: [],
-          disabledPluginSpecs: [],
           settings: {
             prop: ['a', 'b', 'c'],
           },
@@ -152,40 +138,10 @@ describe('getUnusedConfigKeys', () => {
     });
   });
 
-  it('ignores config for plugins that are disabled', async () => {
-    expect(
-      await getUnusedConfigKeys({
-        coreHandledConfigPaths: [],
-        pluginSpecs: [],
-        disabledPluginSpecs: [
-          ({
-            id: 'foo',
-            getConfigPrefix: () => 'foo.bar',
-          } as unknown) as LegacyPluginSpec,
-        ],
-        settings: {
-          foo: {
-            bar: {
-              unused: true,
-            },
-          },
-          plugin: {
-            missingProp: false,
-          },
-        },
-        legacyConfig: getConfig({
-          prop: 'a',
-        }),
-      })
-    ).toEqual(['plugin.missingProp']);
-  });
-
   it('ignores properties managed by the new platform', async () => {
     expect(
       await getUnusedConfigKeys({
         coreHandledConfigPaths: ['core', 'foo.bar'],
-        pluginSpecs: [],
-        disabledPluginSpecs: [],
         settings: {
           core: {
             prop: 'value',
@@ -204,8 +160,6 @@ describe('getUnusedConfigKeys', () => {
     expect(
       await getUnusedConfigKeys({
         coreHandledConfigPaths: ['core', 'array'],
-        pluginSpecs: [],
-        disabledPluginSpecs: [],
         settings: {
           core: {
             prop: 'value',
diff --git a/src/core/server/legacy/config/get_unused_config_keys.ts b/src/core/server/legacy/config/get_unused_config_keys.ts
index c15c3b270df05..5bbe169033e39 100644
--- a/src/core/server/legacy/config/get_unused_config_keys.ts
+++ b/src/core/server/legacy/config/get_unused_config_keys.ts
@@ -19,30 +19,20 @@
 
 import { difference } from 'lodash';
 import { getFlattenedObject } from '@kbn/std';
-import { unset } from '../../../../legacy/utils';
 import { hasConfigPathIntersection } from '../../config';
-import { LegacyPluginSpec, LegacyConfig, LegacyVars } from '../types';
+import { LegacyConfig, LegacyVars } from '../types';
 
 const getFlattenedKeys = (object: object) => Object.keys(getFlattenedObject(object));
 
 export async function getUnusedConfigKeys({
   coreHandledConfigPaths,
-  pluginSpecs,
-  disabledPluginSpecs,
   settings,
   legacyConfig,
 }: {
   coreHandledConfigPaths: string[];
-  pluginSpecs: LegacyPluginSpec[];
-  disabledPluginSpecs: LegacyPluginSpec[];
   settings: LegacyVars;
   legacyConfig: LegacyConfig;
 }) {
-  // remove config values from disabled plugins
-  for (const spec of disabledPluginSpecs) {
-    unset(settings, spec.getConfigPrefix());
-  }
-
   const inputKeys = getFlattenedKeys(settings);
   const appliedKeys = getFlattenedKeys(legacyConfig.get());
 
diff --git a/src/core/server/legacy/index.ts b/src/core/server/legacy/index.ts
index 6b0963e3129c6..1a0bc8955be0f 100644
--- a/src/core/server/legacy/index.ts
+++ b/src/core/server/legacy/index.ts
@@ -20,8 +20,6 @@
 /** @internal */
 export { ensureValidConfiguration } from './config';
 /** @internal */
-export { LegacyInternals } from './legacy_internals';
-/** @internal */
 export { LegacyService, ILegacyService } from './legacy_service';
 /** @internal */
 export * from './types';
diff --git a/src/core/server/legacy/legacy_internals.test.ts b/src/core/server/legacy/legacy_internals.test.ts
deleted file mode 100644
index 935e36a989a0c..0000000000000
--- a/src/core/server/legacy/legacy_internals.test.ts
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { Server } from 'hapi';
-
-import { configMock } from '../config/mocks';
-import { httpServiceMock } from '../http/http_service.mock';
-import { httpServerMock } from '../http/http_server.mocks';
-import { findLegacyPluginSpecsMock } from './legacy_service.test.mocks';
-import { LegacyInternals } from './legacy_internals';
-import { ILegacyInternals, LegacyConfig, LegacyVars, LegacyUiExports } from './types';
-
-function varsProvider(vars: LegacyVars, configValue?: any) {
-  return {
-    fn: jest.fn().mockReturnValue(vars),
-    pluginSpec: {
-      readConfigValue: jest.fn().mockReturnValue(configValue),
-    },
-  };
-}
-
-describe('LegacyInternals', () => {
-  describe('getInjectedUiAppVars()', () => {
-    let uiExports: LegacyUiExports;
-    let config: LegacyConfig;
-    let server: Server;
-    let legacyInternals: ILegacyInternals;
-
-    beforeEach(async () => {
-      uiExports = findLegacyPluginSpecsMock().uiExports;
-      config = configMock.create() as any;
-      server = httpServiceMock.createInternalSetupContract().server;
-      legacyInternals = new LegacyInternals(uiExports, config, server);
-    });
-
-    it('gets with no injectors', async () => {
-      await expect(legacyInternals.getInjectedUiAppVars('core')).resolves.toMatchInlineSnapshot(
-        `Object {}`
-      );
-    });
-
-    it('gets with no matching injectors', async () => {
-      const injector = jest.fn().mockResolvedValue({ not: 'core' });
-      legacyInternals.injectUiAppVars('not-core', injector);
-
-      await expect(legacyInternals.getInjectedUiAppVars('core')).resolves.toMatchInlineSnapshot(
-        `Object {}`
-      );
-      expect(injector).not.toHaveBeenCalled();
-    });
-
-    it('gets with single matching injector', async () => {
-      const injector = jest.fn().mockResolvedValue({ is: 'core' });
-      legacyInternals.injectUiAppVars('core', injector);
-
-      await expect(legacyInternals.getInjectedUiAppVars('core')).resolves.toMatchInlineSnapshot(`
-        Object {
-          "is": "core",
-        }
-      `);
-      expect(injector).toHaveBeenCalled();
-    });
-
-    it('gets with multiple matching injectors', async () => {
-      const injectors = [
-        jest.fn().mockResolvedValue({ is: 'core' }),
-        jest.fn().mockReturnValue({ sync: 'injector' }),
-        jest.fn().mockResolvedValue({ is: 'merged-core' }),
-      ];
-
-      injectors.forEach((injector) => legacyInternals.injectUiAppVars('core', injector));
-
-      await expect(legacyInternals.getInjectedUiAppVars('core')).resolves.toMatchInlineSnapshot(`
-        Object {
-          "is": "merged-core",
-          "sync": "injector",
-        }
-      `);
-      expect(injectors[0]).toHaveBeenCalled();
-      expect(injectors[1]).toHaveBeenCalled();
-      expect(injectors[2]).toHaveBeenCalled();
-    });
-  });
-
-  describe('getVars()', () => {
-    let uiExports: LegacyUiExports;
-    let config: LegacyConfig;
-    let server: Server;
-    let legacyInternals: LegacyInternals;
-
-    beforeEach(async () => {
-      uiExports = findLegacyPluginSpecsMock().uiExports;
-      config = configMock.create() as any;
-      server = httpServiceMock.createInternalSetupContract().server;
-      legacyInternals = new LegacyInternals(uiExports, config, server);
-    });
-
-    it('gets: no default injectors, no injected vars replacers, no ui app injectors, no inject arg', async () => {
-      const vars = await legacyInternals.getVars('core', httpServerMock.createRawRequest());
-
-      expect(vars).toMatchInlineSnapshot(`Object {}`);
-    });
-
-    it('gets: with default injectors, no injected vars replacers, no ui app injectors, no inject arg', async () => {
-      uiExports.defaultInjectedVarProviders = [
-        varsProvider({ alpha: 'alpha' }),
-        varsProvider({ gamma: 'gamma' }),
-        varsProvider({ alpha: 'beta' }),
-      ];
-
-      const vars = await legacyInternals.getVars('core', httpServerMock.createRawRequest());
-
-      expect(vars).toMatchInlineSnapshot(`
-        Object {
-          "alpha": "beta",
-          "gamma": "gamma",
-        }
-      `);
-    });
-
-    it('gets: no default injectors, with injected vars replacers, with ui app injectors, no inject arg', async () => {
-      uiExports.injectedVarsReplacers = [
-        jest.fn(async (vars) => ({ ...vars, added: 'key' })),
-        jest.fn((vars) => vars),
-        jest.fn((vars) => ({ replaced: 'all' })),
-        jest.fn(async (vars) => ({ ...vars, added: 'last-key' })),
-      ];
-
-      const request = httpServerMock.createRawRequest();
-      const vars = await legacyInternals.getVars('core', request);
-
-      expect(vars).toMatchInlineSnapshot(`
-        Object {
-          "added": "last-key",
-          "replaced": "all",
-        }
-      `);
-    });
-
-    it('gets: no default injectors, no injected vars replacers, with ui app injectors, no inject arg', async () => {
-      legacyInternals.injectUiAppVars('core', async () => ({ is: 'core' }));
-      legacyInternals.injectUiAppVars('core', () => ({ sync: 'injector' }));
-      legacyInternals.injectUiAppVars('core', async () => ({ is: 'merged-core' }));
-
-      const vars = await legacyInternals.getVars('core', httpServerMock.createRawRequest());
-
-      expect(vars).toMatchInlineSnapshot(`
-        Object {
-          "is": "merged-core",
-          "sync": "injector",
-        }
-      `);
-    });
-
-    it('gets: no default injectors, no injected vars replacers, no ui app injectors, with inject arg', async () => {
-      const vars = await legacyInternals.getVars('core', httpServerMock.createRawRequest(), {
-        injected: 'arg',
-      });
-
-      expect(vars).toMatchInlineSnapshot(`
-        Object {
-          "injected": "arg",
-        }
-      `);
-    });
-
-    it('gets: with default injectors, with injected vars replacers, with ui app injectors, with inject arg', async () => {
-      uiExports.defaultInjectedVarProviders = [
-        varsProvider({ alpha: 'alpha' }),
-        varsProvider({ gamma: 'gamma' }),
-        varsProvider({ alpha: 'beta' }),
-      ];
-      uiExports.injectedVarsReplacers = [jest.fn(async (vars) => ({ ...vars, gamma: 'delta' }))];
-
-      legacyInternals.injectUiAppVars('core', async () => ({ is: 'core' }));
-      legacyInternals.injectUiAppVars('core', () => ({ sync: 'injector' }));
-      legacyInternals.injectUiAppVars('core', async () => ({ is: 'merged-core' }));
-
-      const vars = await legacyInternals.getVars('core', httpServerMock.createRawRequest(), {
-        injected: 'arg',
-        sync: 'arg',
-      });
-
-      expect(vars).toMatchInlineSnapshot(`
-        Object {
-          "alpha": "beta",
-          "gamma": "delta",
-          "injected": "arg",
-          "is": "merged-core",
-          "sync": "arg",
-        }
-      `);
-    });
-  });
-});
diff --git a/src/core/server/legacy/legacy_internals.ts b/src/core/server/legacy/legacy_internals.ts
deleted file mode 100644
index 628ca4ed12f6b..0000000000000
--- a/src/core/server/legacy/legacy_internals.ts
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { Server } from 'hapi';
-
-import { KibanaRequest, LegacyRequest } from '../http';
-import { ensureRawRequest } from '../http/router';
-import { mergeVars } from './merge_vars';
-import { ILegacyInternals, LegacyVars, VarsInjector, LegacyConfig, LegacyUiExports } from './types';
-
-/**
- * @internal
- * @deprecated
- */
-export class LegacyInternals implements ILegacyInternals {
-  private readonly injectors = new Map<string, Set<VarsInjector>>();
-  private cachedDefaultVars?: LegacyVars;
-
-  constructor(
-    private readonly uiExports: LegacyUiExports,
-    private readonly config: LegacyConfig,
-    private readonly server: Server
-  ) {}
-
-  private get defaultVars(): LegacyVars {
-    if (this.cachedDefaultVars) {
-      return this.cachedDefaultVars;
-    }
-
-    const { defaultInjectedVarProviders = [] } = this.uiExports;
-
-    return (this.cachedDefaultVars = defaultInjectedVarProviders.reduce(
-      (vars, { fn, pluginSpec }) =>
-        mergeVars(vars, fn(this.server, pluginSpec.readConfigValue(this.config, []))),
-      {}
-    ));
-  }
-
-  private replaceVars(vars: LegacyVars, request: KibanaRequest | LegacyRequest) {
-    const { injectedVarsReplacers = [] } = this.uiExports;
-
-    return injectedVarsReplacers.reduce(
-      async (injected, replacer) =>
-        replacer(await injected, ensureRawRequest(request), this.server),
-      Promise.resolve(vars)
-    );
-  }
-
-  public injectUiAppVars(id: string, injector: VarsInjector) {
-    if (!this.injectors.has(id)) {
-      this.injectors.set(id, new Set());
-    }
-
-    this.injectors.get(id)!.add(injector);
-  }
-
-  public getInjectedUiAppVars(id: string) {
-    return [...(this.injectors.get(id) || [])].reduce(
-      async (promise, injector) => ({
-        ...(await promise),
-        ...(await injector()),
-      }),
-      Promise.resolve<LegacyVars>({})
-    );
-  }
-
-  public async getVars(
-    id: string,
-    request: KibanaRequest | LegacyRequest,
-    injected: LegacyVars = {}
-  ) {
-    return this.replaceVars(
-      mergeVars(this.defaultVars, await this.getInjectedUiAppVars(id), injected),
-      request
-    );
-  }
-}
diff --git a/src/core/server/legacy/legacy_service.mock.ts b/src/core/server/legacy/legacy_service.mock.ts
index ab501bd6bb53b..781874f702cf8 100644
--- a/src/core/server/legacy/legacy_service.mock.ts
+++ b/src/core/server/legacy/legacy_service.mock.ts
@@ -18,26 +18,13 @@
  */
 import type { PublicMethodsOf } from '@kbn/utility-types';
 import { LegacyService } from './legacy_service';
-import { LegacyConfig, LegacyServiceDiscoverPlugins, LegacyServiceSetupDeps } from './types';
+import { LegacyConfig, LegacyServiceSetupDeps } from './types';
 
 type LegacyServiceMock = jest.Mocked<PublicMethodsOf<LegacyService> & { legacyId: symbol }>;
 
-const createDiscoverPluginsMock = (): LegacyServiceDiscoverPlugins => ({
-  pluginSpecs: [],
-  uiExports: {},
-  navLinks: [],
-  pluginExtendedConfig: {
-    get: jest.fn(),
-    has: jest.fn(),
-    set: jest.fn(),
-  },
-  disabledPluginSpecs: [],
-  settings: {},
-});
-
 const createLegacyServiceMock = (): LegacyServiceMock => ({
   legacyId: Symbol(),
-  discoverPlugins: jest.fn().mockResolvedValue(createDiscoverPluginsMock()),
+  setupLegacyConfig: jest.fn(),
   setup: jest.fn(),
   start: jest.fn(),
   stop: jest.fn(),
@@ -52,6 +39,5 @@ const createLegacyConfigMock = (): jest.Mocked<LegacyConfig> => ({
 export const legacyServiceMock = {
   create: createLegacyServiceMock,
   createSetupContract: (deps: LegacyServiceSetupDeps) => createLegacyServiceMock().setup(deps),
-  createDiscoverPlugins: createDiscoverPluginsMock,
   createLegacyConfig: createLegacyConfigMock,
 };
diff --git a/src/core/server/legacy/legacy_service.test.mocks.ts b/src/core/server/legacy/legacy_service.test.mocks.ts
deleted file mode 100644
index 9ad554d63add0..0000000000000
--- a/src/core/server/legacy/legacy_service.test.mocks.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { LegacyVars } from './types';
-
-export const findLegacyPluginSpecsMock = jest.fn().mockImplementation((settings: LegacyVars) => ({
-  pluginSpecs: [],
-  pluginExtendedConfig: {
-    has: jest.fn(),
-    get: jest.fn().mockReturnValue(settings),
-    set: jest.fn(),
-  },
-  disabledPluginSpecs: [],
-  uiExports: {},
-  navLinks: [],
-}));
-jest.doMock('./plugins/find_legacy_plugin_specs', () => ({
-  findLegacyPluginSpecs: findLegacyPluginSpecsMock,
-}));
-
-export const logLegacyThirdPartyPluginDeprecationWarningMock = jest.fn();
-jest.doMock('./plugins/log_legacy_plugins_warning', () => ({
-  logLegacyThirdPartyPluginDeprecationWarning: logLegacyThirdPartyPluginDeprecationWarningMock,
-}));
diff --git a/src/core/server/legacy/legacy_service.test.ts b/src/core/server/legacy/legacy_service.test.ts
index a6fe95deb3979..57009f0d35c16 100644
--- a/src/core/server/legacy/legacy_service.test.ts
+++ b/src/core/server/legacy/legacy_service.test.ts
@@ -19,10 +19,6 @@
 
 jest.mock('../../../legacy/server/kbn_server');
 jest.mock('./cluster_manager');
-import {
-  findLegacyPluginSpecsMock,
-  logLegacyThirdPartyPluginDeprecationWarningMock,
-} from './legacy_service.test.mocks';
 
 import { BehaviorSubject, throwError } from 'rxjs';
 import { REPO_ROOT } from '@kbn/dev-utils';
@@ -44,8 +40,7 @@ import { capabilitiesServiceMock } from '../capabilities/capabilities_service.mo
 import { httpResourcesMock } from '../http_resources/http_resources_service.mock';
 import { setupMock as renderingServiceMock } from '../rendering/__mocks__/rendering_service';
 import { environmentServiceMock } from '../environment/environment_service.mock';
-import { findLegacyPluginSpecs } from './plugins';
-import { LegacyVars, LegacyServiceSetupDeps, LegacyServiceStartDeps } from './types';
+import { LegacyServiceSetupDeps, LegacyServiceStartDeps } from './types';
 import { LegacyService } from './legacy_service';
 import { coreMock } from '../mocks';
 import { statusServiceMock } from '../status/status_service.mock';
@@ -73,7 +68,6 @@ beforeEach(() => {
   configService = configServiceMock.create();
   environmentSetup = environmentServiceMock.createSetupContract();
 
-  findLegacyPluginSpecsMock.mockClear();
   MockKbnServer.prototype.ready = jest.fn().mockReturnValue(Promise.resolve());
   MockKbnServer.prototype.listen = jest.fn();
 
@@ -149,10 +143,10 @@ describe('once LegacyService is set up with connection info', () => {
       coreId,
       env,
       logger,
-      configService: configService as any,
+      configService,
     });
 
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await legacyService.start(startDeps);
 
@@ -160,13 +154,14 @@ describe('once LegacyService is set up with connection info', () => {
     expect(MockKbnServer).toHaveBeenCalledWith(
       { path: { autoListen: true }, server: { autoListen: true } }, // Because of the mock, path also gets the value
       expect.objectContaining({ get: expect.any(Function) }),
-      expect.any(Object),
-      { disabledPluginSpecs: [], pluginSpecs: [], uiExports: {}, navLinks: [] }
+      expect.any(Object)
+    );
+    expect(MockKbnServer.mock.calls[0][1].get()).toEqual(
+      expect.objectContaining({
+        path: expect.objectContaining({ autoListen: true }),
+        server: expect.objectContaining({ autoListen: true }),
+      })
     );
-    expect(MockKbnServer.mock.calls[0][1].get()).toEqual({
-      path: { autoListen: true },
-      server: { autoListen: true },
-    });
 
     const [mockKbnServer] = MockKbnServer.mock.instances;
     expect(mockKbnServer.listen).toHaveBeenCalledTimes(1);
@@ -182,7 +177,7 @@ describe('once LegacyService is set up with connection info', () => {
       logger,
       configService: configService as any,
     });
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await legacyService.start(startDeps);
 
@@ -190,13 +185,12 @@ describe('once LegacyService is set up with connection info', () => {
     expect(MockKbnServer).toHaveBeenCalledWith(
       { path: { autoListen: false }, server: { autoListen: true } },
       expect.objectContaining({ get: expect.any(Function) }),
-      expect.any(Object),
-      { disabledPluginSpecs: [], pluginSpecs: [], uiExports: {}, navLinks: [] }
+      expect.any(Object)
     );
-    expect(MockKbnServer.mock.calls[0][1].get()).toEqual({
-      path: { autoListen: false },
-      server: { autoListen: true },
-    });
+
+    const legacyConfig = MockKbnServer.mock.calls[0][1].get();
+    expect(legacyConfig.path.autoListen).toBe(false);
+    expect(legacyConfig.server.autoListen).toBe(true);
 
     const [mockKbnServer] = MockKbnServer.mock.instances;
     expect(mockKbnServer.ready).toHaveBeenCalledTimes(1);
@@ -214,7 +208,7 @@ describe('once LegacyService is set up with connection info', () => {
       configService: configService as any,
     });
 
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await expect(legacyService.start(startDeps)).rejects.toThrowErrorMatchingInlineSnapshot(
       `"something failed"`
@@ -234,11 +228,11 @@ describe('once LegacyService is set up with connection info', () => {
       configService: configService as any,
     });
 
-    await expect(legacyService.discoverPlugins()).rejects.toThrowErrorMatchingInlineSnapshot(
+    await expect(legacyService.setupLegacyConfig()).rejects.toThrowErrorMatchingInlineSnapshot(
       `"something failed"`
     );
     await expect(legacyService.setup(setupDeps)).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"Legacy service has not discovered legacy plugins yet. Ensure LegacyService.discoverPlugins() is called before LegacyService.setup()"`
+      `"Legacy config not initialized yet. Ensure LegacyService.setupLegacyConfig() is called before LegacyService.setup()"`
     );
     await expect(legacyService.start(startDeps)).rejects.toThrowErrorMatchingInlineSnapshot(
       `"Legacy service is not setup yet."`
@@ -255,7 +249,7 @@ describe('once LegacyService is set up with connection info', () => {
       logger,
       configService: configService as any,
     });
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await legacyService.start(startDeps);
 
@@ -276,7 +270,7 @@ describe('once LegacyService is set up with connection info', () => {
       logger,
       configService: configService as any,
     });
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await legacyService.start(startDeps);
 
@@ -301,7 +295,7 @@ describe('once LegacyService is set up with connection info', () => {
       logger,
       configService: configService as any,
     });
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await legacyService.start(startDeps);
 
@@ -321,7 +315,7 @@ describe('once LegacyService is set up without connection info', () => {
   let legacyService: LegacyService;
   beforeEach(async () => {
     legacyService = new LegacyService({ coreId, env, logger, configService: configService as any });
-    await legacyService.discoverPlugins();
+    await legacyService.setupLegacyConfig();
     await legacyService.setup(setupDeps);
     await legacyService.start(startDeps);
   });
@@ -331,13 +325,13 @@ describe('once LegacyService is set up without connection info', () => {
     expect(MockKbnServer).toHaveBeenCalledWith(
       { path: {}, server: { autoListen: true } },
       expect.objectContaining({ get: expect.any(Function) }),
-      expect.any(Object),
-      { disabledPluginSpecs: [], pluginSpecs: [], uiExports: {}, navLinks: [] }
+      expect.any(Object)
+    );
+    expect(MockKbnServer.mock.calls[0][1].get()).toEqual(
+      expect.objectContaining({
+        server: expect.objectContaining({ autoListen: true }),
+      })
     );
-    expect(MockKbnServer.mock.calls[0][1].get()).toEqual({
-      path: {},
-      server: { autoListen: true },
-    });
   });
 
   test('reconfigures logging configuration if new config is received.', async () => {
@@ -375,7 +369,7 @@ describe('once LegacyService is set up in `devClusterMaster` mode', () => {
       configService: configService as any,
     });
 
-    await devClusterLegacyService.discoverPlugins();
+    await devClusterLegacyService.setupLegacyConfig();
     await devClusterLegacyService.setup(setupDeps);
     await devClusterLegacyService.start(startDeps);
 
@@ -404,7 +398,7 @@ describe('once LegacyService is set up in `devClusterMaster` mode', () => {
       configService: configService as any,
     });
 
-    await devClusterLegacyService.discoverPlugins();
+    await devClusterLegacyService.setupLegacyConfig();
     await devClusterLegacyService.setup(setupDeps);
     await devClusterLegacyService.start(startDeps);
 
@@ -434,50 +428,6 @@ describe('start', () => {
   });
 });
 
-describe('#discoverPlugins()', () => {
-  it('calls findLegacyPluginSpecs with correct parameters', async () => {
-    const legacyService = new LegacyService({
-      coreId,
-      env,
-      logger,
-      configService: configService as any,
-    });
-
-    await legacyService.discoverPlugins();
-    expect(findLegacyPluginSpecs).toHaveBeenCalledTimes(1);
-    expect(findLegacyPluginSpecs).toHaveBeenCalledWith(expect.any(Object), logger, env.packageInfo);
-  });
-
-  it(`logs deprecations for legacy third party plugins`, async () => {
-    const pluginSpecs = [{ getId: () => 'pluginA' }, { getId: () => 'pluginB' }];
-    findLegacyPluginSpecsMock.mockImplementation(
-      (settings) =>
-        Promise.resolve({
-          pluginSpecs,
-          pluginExtendedConfig: settings,
-          disabledPluginSpecs: [],
-          uiExports: {},
-          navLinks: [],
-        }) as any
-    );
-
-    const legacyService = new LegacyService({
-      coreId,
-      env,
-      logger,
-      configService: configService as any,
-    });
-
-    await legacyService.discoverPlugins();
-
-    expect(logLegacyThirdPartyPluginDeprecationWarningMock).toHaveBeenCalledTimes(1);
-    expect(logLegacyThirdPartyPluginDeprecationWarningMock).toHaveBeenCalledWith({
-      specs: pluginSpecs,
-      log: expect.any(Object),
-    });
-  });
-});
-
 test('Sets the server.uuid property on the legacy configuration', async () => {
   configService.atPath.mockReturnValue(new BehaviorSubject({ autoListen: true }));
   const legacyService = new LegacyService({
@@ -489,23 +439,8 @@ test('Sets the server.uuid property on the legacy configuration', async () => {
 
   environmentSetup.instanceUuid = 'UUID_FROM_SERVICE';
 
-  const configSetMock = jest.fn();
-
-  findLegacyPluginSpecsMock.mockImplementation((settings: LegacyVars) => ({
-    pluginSpecs: [],
-    pluginExtendedConfig: {
-      has: jest.fn(),
-      get: jest.fn().mockReturnValue(settings),
-      set: configSetMock,
-    },
-    disabledPluginSpecs: [],
-    uiExports: {},
-    navLinks: [],
-  }));
-
-  await legacyService.discoverPlugins();
+  const { legacyConfig } = await legacyService.setupLegacyConfig();
   await legacyService.setup(setupDeps);
 
-  expect(configSetMock).toHaveBeenCalledTimes(1);
-  expect(configSetMock).toHaveBeenCalledWith('server.uuid', 'UUID_FROM_SERVICE');
+  expect(legacyConfig.get('server.uuid')).toBe('UUID_FROM_SERVICE');
 });
diff --git a/src/core/server/legacy/legacy_service.ts b/src/core/server/legacy/legacy_service.ts
index 4dc22be2a9971..086e20c98c1a3 100644
--- a/src/core/server/legacy/legacy_service.ts
+++ b/src/core/server/legacy/legacy_service.ts
@@ -16,11 +16,14 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import type { PublicMethodsOf } from '@kbn/utility-types';
+
 import { combineLatest, ConnectableObservable, EMPTY, Observable, Subscription } from 'rxjs';
 import { first, map, publishReplay, tap } from 'rxjs/operators';
-
+import type { PublicMethodsOf } from '@kbn/utility-types';
 import { PathConfigType } from '@kbn/utils';
+
+// @ts-expect-error legacy config class
+import { Config as LegacyConfigClass } from '../../../legacy/server/config';
 import { CoreService } from '../../types';
 import { Config } from '../config';
 import { CoreContext } from '../core_context';
@@ -28,17 +31,7 @@ import { CspConfigType, config as cspConfig } from '../csp';
 import { DevConfig, DevConfigType, config as devConfig } from '../dev';
 import { BasePathProxyServer, HttpConfig, HttpConfigType, config as httpConfig } from '../http';
 import { Logger } from '../logging';
-import { findLegacyPluginSpecs, logLegacyThirdPartyPluginDeprecationWarning } from './plugins';
-import {
-  ILegacyInternals,
-  LegacyServiceSetupDeps,
-  LegacyServiceStartDeps,
-  LegacyPlugins,
-  LegacyServiceDiscoverPlugins,
-  LegacyConfig,
-  LegacyVars,
-} from './types';
-import { LegacyInternals } from './legacy_internals';
+import { LegacyServiceSetupDeps, LegacyServiceStartDeps, LegacyConfig, LegacyVars } from './types';
 import { CoreSetup, CoreStart } from '..';
 
 interface LegacyKbnServer {
@@ -80,9 +73,7 @@ export class LegacyService implements CoreService {
   private setupDeps?: LegacyServiceSetupDeps;
   private update$?: ConnectableObservable<[Config, PathConfigType]>;
   private legacyRawConfig?: LegacyConfig;
-  private legacyPlugins?: LegacyPlugins;
   private settings?: LegacyVars;
-  public legacyInternals?: ILegacyInternals;
 
   constructor(private readonly coreContext: CoreContext) {
     const { logger, configService } = coreContext;
@@ -97,11 +88,11 @@ export class LegacyService implements CoreService {
     ).pipe(map(([http, csp]) => new HttpConfig(http, csp)));
   }
 
-  public async discoverPlugins(): Promise<LegacyServiceDiscoverPlugins> {
-    this.update$ = combineLatest(
+  public async setupLegacyConfig() {
+    this.update$ = combineLatest([
       this.coreContext.configService.getConfig$(),
-      this.coreContext.configService.atPath<PathConfigType>('path')
-    ).pipe(
+      this.coreContext.configService.atPath<PathConfigType>('path'),
+    ]).pipe(
       tap(([config, pathConfig]) => {
         if (this.kbnServer !== undefined) {
           this.kbnServer.applyLoggingConfiguration(getLegacyRawConfig(config, pathConfig));
@@ -120,74 +111,33 @@ export class LegacyService implements CoreService {
       )
       .toPromise();
 
-    const {
-      pluginSpecs,
-      pluginExtendedConfig,
-      disabledPluginSpecs,
-      uiExports,
-      navLinks,
-    } = await findLegacyPluginSpecs(
-      this.settings,
-      this.coreContext.logger,
-      this.coreContext.env.packageInfo
-    );
-
-    logLegacyThirdPartyPluginDeprecationWarning({
-      specs: pluginSpecs,
-      log: this.log,
-    });
-
-    this.legacyPlugins = {
-      pluginSpecs,
-      disabledPluginSpecs,
-      uiExports,
-      navLinks,
-    };
-
-    this.legacyRawConfig = pluginExtendedConfig;
-
-    // check for unknown uiExport types
-    if (uiExports.unknown && uiExports.unknown.length > 0) {
-      throw new Error(
-        `Unknown uiExport types: ${uiExports.unknown
-          .map(({ pluginSpec, type }) => `${type} from ${pluginSpec.getId()}`)
-          .join(', ')}`
-      );
-    }
+    this.legacyRawConfig = LegacyConfigClass.withDefaultSchema(this.settings);
 
     return {
-      pluginSpecs,
-      disabledPluginSpecs,
-      uiExports,
-      navLinks,
-      pluginExtendedConfig,
       settings: this.settings,
+      legacyConfig: this.legacyRawConfig!,
     };
   }
 
   public async setup(setupDeps: LegacyServiceSetupDeps) {
     this.log.debug('setting up legacy service');
 
-    if (!this.legacyPlugins) {
+    if (!this.legacyRawConfig) {
       throw new Error(
-        'Legacy service has not discovered legacy plugins yet. Ensure LegacyService.discoverPlugins() is called before LegacyService.setup()'
+        'Legacy config not initialized yet. Ensure LegacyService.setupLegacyConfig() is called before LegacyService.setup()'
       );
     }
 
     // propagate the instance uuid to the legacy config, as it was the legacy way to access it.
     this.legacyRawConfig!.set('server.uuid', setupDeps.core.environment.instanceUuid);
+
     this.setupDeps = setupDeps;
-    this.legacyInternals = new LegacyInternals(
-      this.legacyPlugins.uiExports,
-      this.legacyRawConfig!,
-      setupDeps.core.http.server
-    );
   }
 
   public async start(startDeps: LegacyServiceStartDeps) {
     const { setupDeps } = this;
 
-    if (!setupDeps || !this.legacyPlugins) {
+    if (!setupDeps || !this.legacyRawConfig) {
       throw new Error('Legacy service is not setup yet.');
     }
 
@@ -201,8 +151,7 @@ export class LegacyService implements CoreService {
         this.settings!,
         this.legacyRawConfig!,
         setupDeps,
-        startDeps,
-        this.legacyPlugins!
+        startDeps
       );
     }
   }
@@ -245,8 +194,7 @@ export class LegacyService implements CoreService {
     settings: LegacyVars,
     config: LegacyConfig,
     setupDeps: LegacyServiceSetupDeps,
-    startDeps: LegacyServiceStartDeps,
-    legacyPlugins: LegacyPlugins
+    startDeps: LegacyServiceStartDeps
   ) {
     const coreStart: CoreStart = {
       capabilities: startDeps.core.capabilities,
@@ -337,36 +285,26 @@ export class LegacyService implements CoreService {
 
     // eslint-disable-next-line @typescript-eslint/no-var-requires
     const KbnServer = require('../../../legacy/server/kbn_server');
-    const kbnServer: LegacyKbnServer = new KbnServer(
-      settings,
-      config,
-      {
-        env: {
-          mode: this.coreContext.env.mode,
-          packageInfo: this.coreContext.env.packageInfo,
-        },
-        setupDeps: {
-          core: coreSetup,
-          plugins: setupDeps.plugins,
-        },
-        startDeps: {
-          core: coreStart,
-          plugins: startDeps.plugins,
-        },
-        __internals: {
-          http: {
-            registerStaticDir: setupDeps.core.http.registerStaticDir,
-          },
-          hapiServer: setupDeps.core.http.server,
-          uiPlugins: setupDeps.uiPlugins,
-          elasticsearch: setupDeps.core.elasticsearch,
-          rendering: setupDeps.core.rendering,
-          legacy: this.legacyInternals,
-        },
-        logger: this.coreContext.logger,
+    const kbnServer: LegacyKbnServer = new KbnServer(settings, config, {
+      env: {
+        mode: this.coreContext.env.mode,
+        packageInfo: this.coreContext.env.packageInfo,
       },
-      legacyPlugins
-    );
+      setupDeps: {
+        core: coreSetup,
+        plugins: setupDeps.plugins,
+      },
+      startDeps: {
+        core: coreStart,
+        plugins: startDeps.plugins,
+      },
+      __internals: {
+        hapiServer: setupDeps.core.http.server,
+        uiPlugins: setupDeps.uiPlugins,
+        rendering: setupDeps.core.rendering,
+      },
+      logger: this.coreContext.logger,
+    });
 
     // The kbnWorkerType check is necessary to prevent the repl
     // from being started multiple times in different processes.
diff --git a/src/core/server/legacy/plugins/collect_ui_exports.js b/src/core/server/legacy/plugins/collect_ui_exports.js
deleted file mode 100644
index 842ab554d79d1..0000000000000
--- a/src/core/server/legacy/plugins/collect_ui_exports.js
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-// eslint-disable-next-line @kbn/eslint/no-restricted-paths
-export { collectUiExports } from '../../../../legacy/ui/ui_exports/collect_ui_exports';
diff --git a/src/core/server/legacy/plugins/find_legacy_plugin_specs.ts b/src/core/server/legacy/plugins/find_legacy_plugin_specs.ts
deleted file mode 100644
index cb4277b130a88..0000000000000
--- a/src/core/server/legacy/plugins/find_legacy_plugin_specs.ts
+++ /dev/null
@@ -1,135 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { Observable, merge, forkJoin } from 'rxjs';
-import { toArray, tap, distinct, map } from 'rxjs/operators';
-
-import {
-  findPluginSpecs,
-  defaultConfig,
-  // @ts-expect-error
-} from '../../../../legacy/plugin_discovery/find_plugin_specs.js';
-// @ts-expect-error
-import { collectUiExports as collectLegacyUiExports } from './collect_ui_exports';
-
-import { LoggerFactory } from '../../logging';
-import { PackageInfo } from '../../config';
-import { LegacyUiExports, LegacyPluginSpec, LegacyPluginPack, LegacyConfig } from '../types';
-
-export async function findLegacyPluginSpecs(
-  settings: unknown,
-  loggerFactory: LoggerFactory,
-  packageInfo: PackageInfo
-) {
-  const configToMutate: LegacyConfig = defaultConfig(settings);
-  const {
-    pack$,
-    invalidDirectoryError$,
-    invalidPackError$,
-    otherError$,
-    deprecation$,
-    invalidVersionSpec$,
-    spec$,
-    disabledSpec$,
-  }: {
-    pack$: Observable<LegacyPluginPack>;
-    invalidDirectoryError$: Observable<{ path: string }>;
-    invalidPackError$: Observable<{ path: string }>;
-    otherError$: Observable<unknown>;
-    deprecation$: Observable<{ spec: LegacyPluginSpec; message: string }>;
-    invalidVersionSpec$: Observable<LegacyPluginSpec>;
-    spec$: Observable<LegacyPluginSpec>;
-    disabledSpec$: Observable<LegacyPluginSpec>;
-  } = findPluginSpecs(settings, configToMutate) as any;
-
-  const logger = loggerFactory.get('legacy-plugins');
-
-  const log$ = merge(
-    pack$.pipe(
-      tap((definition) => {
-        const path = definition.getPath();
-        logger.debug(`Found plugin at ${path}`, { path });
-      })
-    ),
-
-    invalidDirectoryError$.pipe(
-      tap((error) => {
-        logger.warn(`Unable to scan directory for plugins "${error.path}"`, {
-          err: error,
-          dir: error.path,
-        });
-      })
-    ),
-
-    invalidPackError$.pipe(
-      tap((error) => {
-        logger.warn(`Skipping non-plugin directory at ${error.path}`, {
-          path: error.path,
-        });
-      })
-    ),
-
-    otherError$.pipe(
-      tap((error) => {
-        // rethrow unhandled errors, which will fail the server
-        throw error;
-      })
-    ),
-
-    invalidVersionSpec$.pipe(
-      map((spec) => {
-        const name = spec.getId();
-        const pluginVersion = spec.getExpectedKibanaVersion();
-        const kibanaVersion = packageInfo.version;
-        return `Plugin "${name}" was disabled because it expected Kibana version "${pluginVersion}", and found "${kibanaVersion}".`;
-      }),
-      distinct(),
-      tap((message) => {
-        logger.warn(message);
-      })
-    ),
-
-    deprecation$.pipe(
-      tap(({ spec, message }) => {
-        const deprecationLogger = loggerFactory.get(
-          'plugins',
-          spec.getConfigPrefix(),
-          'config',
-          'deprecation'
-        );
-        deprecationLogger.warn(message);
-      })
-    )
-  );
-
-  const [disabledPluginSpecs, pluginSpecs] = await forkJoin(
-    disabledSpec$.pipe(toArray()),
-    spec$.pipe(toArray()),
-    log$.pipe(toArray())
-  ).toPromise();
-  const uiExports: LegacyUiExports = collectLegacyUiExports(pluginSpecs);
-
-  return {
-    disabledPluginSpecs,
-    pluginSpecs,
-    pluginExtendedConfig: configToMutate,
-    uiExports,
-    navLinks: [],
-  };
-}
diff --git a/src/core/server/legacy/plugins/index.ts b/src/core/server/legacy/plugins/index.ts
deleted file mode 100644
index 7ec5dbc1983ab..0000000000000
--- a/src/core/server/legacy/plugins/index.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { findLegacyPluginSpecs } from './find_legacy_plugin_specs';
-export { logLegacyThirdPartyPluginDeprecationWarning } from './log_legacy_plugins_warning';
diff --git a/src/core/server/legacy/plugins/log_legacy_plugins_warning.test.ts b/src/core/server/legacy/plugins/log_legacy_plugins_warning.test.ts
deleted file mode 100644
index 2317f1036ce42..0000000000000
--- a/src/core/server/legacy/plugins/log_legacy_plugins_warning.test.ts
+++ /dev/null
@@ -1,89 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { loggerMock } from '../../logging/logger.mock';
-import { logLegacyThirdPartyPluginDeprecationWarning } from './log_legacy_plugins_warning';
-import { LegacyPluginSpec } from '../types';
-
-const createPluginSpec = ({ id, path }: { id: string; path: string }): LegacyPluginSpec => {
-  return {
-    getId: () => id,
-    getExpectedKibanaVersion: () => 'kibana',
-    getConfigPrefix: () => 'plugin.config',
-    getPack: () => ({
-      getPath: () => path,
-    }),
-  };
-};
-
-describe('logLegacyThirdPartyPluginDeprecationWarning', () => {
-  let log: ReturnType<typeof loggerMock.create>;
-
-  beforeEach(() => {
-    log = loggerMock.create();
-  });
-
-  it('logs warning for third party plugins', () => {
-    logLegacyThirdPartyPluginDeprecationWarning({
-      specs: [createPluginSpec({ id: 'plugin', path: '/some-external-path' })],
-      log,
-    });
-    expect(log.warn).toHaveBeenCalledTimes(1);
-    expect(log.warn.mock.calls[0]).toMatchInlineSnapshot(`
-      Array [
-        "Some installed third party plugin(s) [plugin] are using the legacy plugin format and will no longer work in a future Kibana release. Please refer to https://ela.st/kibana-breaking-changes-8-0 for a list of breaking changes and https://ela.st/kibana-platform-migration for documentation on how to migrate legacy plugins.",
-      ]
-    `);
-  });
-
-  it('lists all the deprecated plugins and only log once', () => {
-    logLegacyThirdPartyPluginDeprecationWarning({
-      specs: [
-        createPluginSpec({ id: 'pluginA', path: '/abs/path/to/pluginA' }),
-        createPluginSpec({ id: 'pluginB', path: '/abs/path/to/pluginB' }),
-        createPluginSpec({ id: 'pluginC', path: '/abs/path/to/pluginC' }),
-      ],
-      log,
-    });
-    expect(log.warn).toHaveBeenCalledTimes(1);
-    expect(log.warn.mock.calls[0]).toMatchInlineSnapshot(`
-      Array [
-        "Some installed third party plugin(s) [pluginA, pluginB, pluginC] are using the legacy plugin format and will no longer work in a future Kibana release. Please refer to https://ela.st/kibana-breaking-changes-8-0 for a list of breaking changes and https://ela.st/kibana-platform-migration for documentation on how to migrate legacy plugins.",
-      ]
-    `);
-  });
-
-  it('does not log warning for internal legacy plugins', () => {
-    logLegacyThirdPartyPluginDeprecationWarning({
-      specs: [
-        createPluginSpec({
-          id: 'plugin',
-          path: '/absolute/path/to/kibana/src/legacy/core_plugins',
-        }),
-        createPluginSpec({
-          id: 'plugin',
-          path: '/absolute/path/to/kibana/x-pack',
-        }),
-      ],
-      log,
-    });
-
-    expect(log.warn).not.toHaveBeenCalled();
-  });
-});
diff --git a/src/core/server/legacy/plugins/log_legacy_plugins_warning.ts b/src/core/server/legacy/plugins/log_legacy_plugins_warning.ts
deleted file mode 100644
index 4a4a1b1b0e60b..0000000000000
--- a/src/core/server/legacy/plugins/log_legacy_plugins_warning.ts
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { Logger } from '../../logging';
-import { LegacyPluginSpec } from '../types';
-
-const internalPaths = ['/src/legacy/core_plugins', '/x-pack'];
-
-// Use shortened URLs so destinations can be updated if/when documentation moves
-// All platform team members have access to edit these
-const breakingChangesUrl = 'https://ela.st/kibana-breaking-changes-8-0';
-const migrationGuideUrl = 'https://ela.st/kibana-platform-migration';
-
-export const logLegacyThirdPartyPluginDeprecationWarning = ({
-  specs,
-  log,
-}: {
-  specs: LegacyPluginSpec[];
-  log: Logger;
-}) => {
-  const thirdPartySpecs = specs.filter(isThirdPartyPluginSpec);
-  if (thirdPartySpecs.length > 0) {
-    const pluginIds = thirdPartySpecs.map((spec) => spec.getId());
-    log.warn(
-      `Some installed third party plugin(s) [${pluginIds.join(
-        ', '
-      )}] are using the legacy plugin format and will no longer work in a future Kibana release. ` +
-        `Please refer to ${breakingChangesUrl} for a list of breaking changes ` +
-        `and ${migrationGuideUrl} for documentation on how to migrate legacy plugins.`
-    );
-  }
-};
-
-const isThirdPartyPluginSpec = (spec: LegacyPluginSpec): boolean => {
-  const pluginPath = spec.getPack().getPath();
-  return !internalPaths.some((internalPath) => pluginPath.indexOf(internalPath) > -1);
-};
diff --git a/src/core/server/legacy/types.ts b/src/core/server/legacy/types.ts
index 1105308fd44cf..12bfddfff1961 100644
--- a/src/core/server/legacy/types.ts
+++ b/src/core/server/legacy/types.ts
@@ -17,10 +17,6 @@
  * under the License.
  */
 
-import { Server } from 'hapi';
-
-import { ChromeNavLink } from '../../public';
-import { KibanaRequest, LegacyRequest } from '../http';
 import { InternalCoreSetup, InternalCoreStart } from '../internal_types';
 import { PluginsServiceSetup, PluginsServiceStart, UiPlugins } from '../plugins';
 import { InternalRenderingServiceSetup } from '../rendering';
@@ -50,91 +46,6 @@ export interface LegacyConfig {
   set(config: LegacyVars): void;
 }
 
-/**
- * @internal
- * @deprecated
- */
-export interface LegacyPluginPack {
-  getPath(): string;
-}
-
-/**
- * @internal
- * @deprecated
- */
-export interface LegacyPluginSpec {
-  getId: () => unknown;
-  getExpectedKibanaVersion: () => string;
-  getConfigPrefix: () => string;
-  getPack: () => LegacyPluginPack;
-}
-
-/**
- * @internal
- * @deprecated
- */
-export interface VarsProvider {
-  fn: (server: Server, configValue: any) => LegacyVars;
-  pluginSpec: {
-    readConfigValue(config: any, key: string | string[]): any;
-  };
-}
-
-/**
- * @internal
- * @deprecated
- */
-export type VarsInjector = () => LegacyVars;
-
-/**
- * @internal
- * @deprecated
- */
-export type VarsReplacer = (
-  vars: LegacyVars,
-  request: LegacyRequest,
-  server: Server
-) => LegacyVars | Promise<LegacyVars>;
-
-/**
- * @internal
- * @deprecated
- */
-export type LegacyNavLinkSpec = Partial<LegacyNavLink> & {
-  id: string;
-  title: string;
-  url: string;
-};
-
-/**
- * @internal
- * @deprecated
- */
-export type LegacyAppSpec = Partial<LegacyNavLink> & {
-  pluginId?: string;
-  listed?: boolean;
-};
-
-/**
- * @internal
- * @deprecated
- */
-export type LegacyNavLink = Omit<ChromeNavLink, 'baseUrl' | 'legacy' | 'order' | 'href'> & {
-  order: number;
-};
-
-/**
- * @internal
- * @deprecated
- */
-export interface LegacyUiExports {
-  defaultInjectedVarProviders?: VarsProvider[];
-  injectedVarsReplacers?: VarsReplacer[];
-  navLinkSpecs?: LegacyNavLinkSpec[] | null;
-  uiAppSpecs?: Array<LegacyAppSpec | undefined>;
-  unknown?: [{ pluginSpec: LegacyPluginSpec; type: unknown }];
-}
-
 /**
  * @public
  * @deprecated
@@ -158,43 +69,7 @@ export interface LegacyServiceStartDeps {
  * @internal
  * @deprecated
  */
-export interface ILegacyInternals {
-  /**
-   * Inject UI app vars for a particular plugin
-   */
-  injectUiAppVars(id: string, injector: VarsInjector): void;
-
-  /**
-   * Get all the merged injected UI app vars for a particular plugin
-   */
-  getInjectedUiAppVars(id: string): Promise<LegacyVars>;
-
-  /**
-   * Get the metadata vars for a particular plugin
-   */
-  getVars(
-    id: string,
-    request: KibanaRequest | LegacyRequest,
-    injected?: LegacyVars
-  ): Promise<LegacyVars>;
-}
-
-/**
- * @internal
- * @deprecated
- */
-export interface LegacyPlugins {
-  disabledPluginSpecs: LegacyPluginSpec[];
-  pluginSpecs: LegacyPluginSpec[];
-  uiExports: LegacyUiExports;
-  navLinks: LegacyNavLink[];
-}
-
-/**
- * @internal
- * @deprecated
- */
-export interface LegacyServiceDiscoverPlugins extends LegacyPlugins {
-  pluginExtendedConfig: LegacyConfig;
+export interface LegacyServiceSetupConfig {
+  legacyConfig: LegacyConfig;
   settings: LegacyVars;
 }
diff --git a/src/core/server/rendering/__mocks__/params.ts b/src/core/server/rendering/__mocks__/params.ts
index 0901cec768cd2..ae3830f703a53 100644
--- a/src/core/server/rendering/__mocks__/params.ts
+++ b/src/core/server/rendering/__mocks__/params.ts
@@ -20,19 +20,16 @@
 import { mockCoreContext } from '../../core_context.mock';
 import { httpServiceMock } from '../../http/http_service.mock';
 import { pluginServiceMock } from '../../plugins/plugins_service.mock';
-import { legacyServiceMock } from '../../legacy/legacy_service.mock';
 import { statusServiceMock } from '../../status/status_service.mock';
 
 const context = mockCoreContext.create();
 const http = httpServiceMock.createInternalSetupContract();
 const uiPlugins = pluginServiceMock.createUiPlugins();
-const legacyPlugins = legacyServiceMock.createDiscoverPlugins();
 const status = statusServiceMock.createInternalSetupContract();
 
 export const mockRenderingServiceParams = context;
 export const mockRenderingSetupDeps = {
   http,
-  legacyPlugins,
   uiPlugins,
   status,
 };
diff --git a/src/core/server/rendering/__mocks__/rendering_service.ts b/src/core/server/rendering/__mocks__/rendering_service.ts
index 179a09b8619b0..01d084f9ae53c 100644
--- a/src/core/server/rendering/__mocks__/rendering_service.ts
+++ b/src/core/server/rendering/__mocks__/rendering_service.ts
@@ -27,11 +27,9 @@ export const setupMock: jest.Mocked<InternalRenderingServiceSetup> = {
   render: jest.fn(),
 };
 export const mockSetup = jest.fn().mockResolvedValue(setupMock);
-export const mockStart = jest.fn();
 export const mockStop = jest.fn();
 export const mockRenderingService: jest.Mocked<IRenderingService> = {
   setup: mockSetup,
-  start: mockStart,
   stop: mockStop,
 };
 export const RenderingService = jest.fn<IRenderingService, [typeof mockRenderingServiceParams]>(
diff --git a/src/core/server/rendering/__snapshots__/rendering_service.test.ts.snap b/src/core/server/rendering/__snapshots__/rendering_service.test.ts.snap
index ab828a1780425..07ca59a48c6b0 100644
--- a/src/core/server/rendering/__snapshots__/rendering_service.test.ts.snap
+++ b/src/core/server/rendering/__snapshots__/rendering_service.test.ts.snap
@@ -27,15 +27,6 @@ Object {
     "translationsUrl": "/mock-server-basepath/translations/en.json",
   },
   "legacyMetadata": Object {
-    "app": Object {},
-    "basePath": "/mock-server-basepath",
-    "branch": Any<String>,
-    "buildNum": Any<Number>,
-    "buildSha": Any<String>,
-    "bundleId": "app:core",
-    "devMode": true,
-    "nav": Array [],
-    "serverName": "http-server-test",
     "uiSettings": Object {
       "defaults": Object {
         "registered": Object {
@@ -44,7 +35,6 @@ Object {
       },
       "user": Object {},
     },
-    "version": Any<String>,
   },
   "serverBasePath": "/mock-server-basepath",
   "uiPlugins": Array [],
@@ -80,15 +70,6 @@ Object {
     "translationsUrl": "/mock-server-basepath/translations/en.json",
   },
   "legacyMetadata": Object {
-    "app": Object {},
-    "basePath": "/mock-server-basepath",
-    "branch": Any<String>,
-    "buildNum": Any<Number>,
-    "buildSha": Any<String>,
-    "bundleId": "app:core",
-    "devMode": true,
-    "nav": Array [],
-    "serverName": "http-server-test",
     "uiSettings": Object {
       "defaults": Object {
         "registered": Object {
@@ -97,7 +78,6 @@ Object {
       },
       "user": Object {},
     },
-    "version": Any<String>,
   },
   "serverBasePath": "/mock-server-basepath",
   "uiPlugins": Array [],
@@ -133,15 +113,6 @@ Object {
     "translationsUrl": "/mock-server-basepath/translations/en.json",
   },
   "legacyMetadata": Object {
-    "app": Object {},
-    "basePath": "/mock-server-basepath",
-    "branch": Any<String>,
-    "buildNum": Any<Number>,
-    "buildSha": Any<String>,
-    "bundleId": "app:core",
-    "devMode": true,
-    "nav": Array [],
-    "serverName": "http-server-test",
     "uiSettings": Object {
       "defaults": Object {
         "registered": Object {
@@ -154,7 +125,6 @@ Object {
         },
       },
     },
-    "version": Any<String>,
   },
   "serverBasePath": "/mock-server-basepath",
   "uiPlugins": Array [],
@@ -190,15 +160,6 @@ Object {
     "translationsUrl": "/translations/en.json",
   },
   "legacyMetadata": Object {
-    "app": Object {},
-    "basePath": "",
-    "branch": Any<String>,
-    "buildNum": Any<Number>,
-    "buildSha": Any<String>,
-    "bundleId": "app:core",
-    "devMode": true,
-    "nav": Array [],
-    "serverName": "http-server-test",
     "uiSettings": Object {
       "defaults": Object {
         "registered": Object {
@@ -207,7 +168,6 @@ Object {
       },
       "user": Object {},
     },
-    "version": Any<String>,
   },
   "serverBasePath": "/mock-server-basepath",
   "uiPlugins": Array [],
@@ -243,15 +203,6 @@ Object {
     "translationsUrl": "/mock-server-basepath/translations/en.json",
   },
   "legacyMetadata": Object {
-    "app": Object {},
-    "basePath": "/mock-server-basepath",
-    "branch": Any<String>,
-    "buildNum": Any<Number>,
-    "buildSha": Any<String>,
-    "bundleId": "app:core",
-    "devMode": true,
-    "nav": Array [],
-    "serverName": "http-server-test",
     "uiSettings": Object {
       "defaults": Object {
         "registered": Object {
@@ -260,7 +211,6 @@ Object {
       },
       "user": Object {},
     },
-    "version": Any<String>,
   },
   "serverBasePath": "/mock-server-basepath",
   "uiPlugins": Array [],
diff --git a/src/core/server/rendering/rendering_service.test.ts b/src/core/server/rendering/rendering_service.test.ts
index 254bafed5b194..08978cd1df64d 100644
--- a/src/core/server/rendering/rendering_service.test.ts
+++ b/src/core/server/rendering/rendering_service.test.ts
@@ -43,12 +43,6 @@ const INJECTED_METADATA = {
       version: expect.any(String),
     },
   },
-  legacyMetadata: {
-    branch: expect.any(String),
-    buildNum: expect.any(Number),
-    buildSha: expect.any(String),
-    version: expect.any(String),
-  },
 };
 
 const { createKibanaRequest, createRawRequest } = httpServerMock;
@@ -72,13 +66,6 @@ describe('RenderingService', () => {
           registered: { name: 'title' },
         });
         render = (await service.setup(mockRenderingSetupDeps)).render;
-        await service.start({
-          legacy: {
-            legacyInternals: {
-              getVars: () => ({}),
-            },
-          },
-        } as any);
       });
 
       it('renders "core" page', async () => {
diff --git a/src/core/server/rendering/rendering_service.tsx b/src/core/server/rendering/rendering_service.tsx
index 7761c89044f6f..738787f940905 100644
--- a/src/core/server/rendering/rendering_service.tsx
+++ b/src/core/server/rendering/rendering_service.tsx
@@ -20,14 +20,11 @@
 import React from 'react';
 import { renderToStaticMarkup } from 'react-dom/server';
 import { take } from 'rxjs/operators';
-
 import { i18n } from '@kbn/i18n';
 
 import { UiPlugins } from '../plugins';
-import { CoreService } from '../../types';
 import { CoreContext } from '../core_context';
 import { Template } from './views';
-import { LegacyService } from '../legacy';
 import {
   IRenderOptions,
   RenderingSetupDeps,
@@ -36,25 +33,20 @@ import {
 } from './types';
 
 /** @internal */
-export class RenderingService implements CoreService<InternalRenderingServiceSetup> {
-  private legacyInternals?: LegacyService['legacyInternals'];
+export class RenderingService {
   constructor(private readonly coreContext: CoreContext) {}
 
   public async setup({
     http,
     status,
-    legacyPlugins,
     uiPlugins,
   }: RenderingSetupDeps): Promise<InternalRenderingServiceSetup> {
     return {
       render: async (
         request,
         uiSettings,
-        { app = { getId: () => 'core' }, includeUserSettings = true, vars }: IRenderOptions = {}
+        { includeUserSettings = true, vars }: IRenderOptions = {}
       ) => {
-        if (!this.legacyInternals) {
-          throw new Error('Cannot render before "start"');
-        }
         const env = {
           mode: this.coreContext.env.mode,
           packageInfo: this.coreContext.env.packageInfo,
@@ -65,7 +57,6 @@ export class RenderingService implements CoreService<InternalRenderingServiceSet
           defaults: uiSettings.getRegistered(),
           user: includeUserSettings ? await uiSettings.getUserProvided() : {},
         };
-        const appId = app.getId();
         const metadata: RenderingMetadata = {
           strictCsp: http.csp.strict,
           uiPublicUrl: `${basePath}/ui`,
@@ -87,7 +78,7 @@ export class RenderingService implements CoreService<InternalRenderingServiceSet
               translationsUrl: `${basePath}/translations/${i18n.getLocale()}.json`,
             },
             csp: { warnLegacyBrowsers: http.csp.warnLegacyBrowsers },
-            vars: vars ?? (await this.legacyInternals!.getVars('core', request)),
+            vars: vars ?? {},
             uiPlugins: await Promise.all(
               [...uiPlugins.public].map(async ([id, plugin]) => ({
                 id,
@@ -96,16 +87,6 @@ export class RenderingService implements CoreService<InternalRenderingServiceSet
               }))
             ),
             legacyMetadata: {
-              app,
-              bundleId: `app:${appId}`,
-              nav: legacyPlugins.navLinks,
-              version: env.packageInfo.version,
-              branch: env.packageInfo.branch,
-              buildNum: env.packageInfo.buildNum,
-              buildSha: env.packageInfo.buildSha,
-              serverName: http.server.name,
-              devMode: env.mode.dev,
-              basePath,
               uiSettings: settings,
             },
           },
@@ -116,10 +97,6 @@ export class RenderingService implements CoreService<InternalRenderingServiceSet
     };
   }
 
-  public async start({ legacy }: { legacy: LegacyService }) {
-    this.legacyInternals = legacy.legacyInternals;
-  }
-
   public async stop() {}
 
   private async getUiConfig(uiPlugins: UiPlugins, pluginId: string) {
diff --git a/src/core/server/rendering/types.ts b/src/core/server/rendering/types.ts
index fb68921ca8636..75bbac1a243e9 100644
--- a/src/core/server/rendering/types.ts
+++ b/src/core/server/rendering/types.ts
@@ -22,7 +22,6 @@ import { i18n } from '@kbn/i18n';
 import { EnvironmentMode, PackageInfo } from '../config';
 import { ICspConfig } from '../csp';
 import { InternalHttpServiceSetup, KibanaRequest, LegacyRequest } from '../http';
-import { LegacyNavLink, LegacyServiceDiscoverPlugins } from '../legacy';
 import { UiPlugins, DiscoveredPlugin } from '../plugins';
 import { IUiSettingsClient, UserProvidedValues } from '../ui_settings';
 import type { InternalStatusServiceSetup } from '../status';
@@ -57,16 +56,6 @@ export interface RenderingMetadata {
       config?: Record<string, unknown>;
     }>;
     legacyMetadata: {
-      app: { getId(): string };
-      bundleId: string;
-      nav: LegacyNavLink[];
-      version: string;
-      branch: string;
-      buildNum: number;
-      buildSha: string;
-      serverName: string;
-      devMode: boolean;
-      basePath: string;
       uiSettings: {
         defaults: Record<string, any>;
         user: Record<string, UserProvidedValues<any>>;
@@ -78,7 +67,6 @@ export interface RenderingMetadata {
 /** @internal */
 export interface RenderingSetupDeps {
   http: InternalHttpServiceSetup;
-  legacyPlugins: LegacyServiceDiscoverPlugins;
   status: InternalStatusServiceSetup;
   uiPlugins: UiPlugins;
 }
@@ -91,14 +79,6 @@ export interface IRenderOptions {
    */
   includeUserSettings?: boolean;
 
-  /**
-   * Render the bootstrapped HTML content for an optional legacy application.
-   * Defaults to `core`.
-   * @deprecated for legacy use only, remove with ui_render_mixin
-   * @internal
-   */
-  app?: { getId(): string };
-
   /**
    * Inject custom vars into the page metadata.
    * @deprecated for legacy use only, remove with ui_render_mixin
diff --git a/src/core/server/server.api.md b/src/core/server/server.api.md
index 8a764d9bd2f66..cc51d27589ce7 100644
--- a/src/core/server/server.api.md
+++ b/src/core/server/server.api.md
@@ -864,10 +864,6 @@ export interface IndexSettingsDeprecationInfo {
 
 // @public (undocumented)
 export interface IRenderOptions {
-    // @internal @deprecated
-    app?: {
-        getId(): string;
-    };
     includeUserSettings?: boolean;
     // @internal @deprecated
     vars?: Record<string, any>;
@@ -1286,21 +1282,6 @@ export class LegacyElasticsearchErrorHelpers {
     static isNotAuthorizedError(error: any): error is LegacyElasticsearchError;
 }
 
-// Warning: (ae-forgotten-export) The symbol "ILegacyInternals" needs to be exported by the entry point index.d.ts
-//
-// @internal @deprecated (undocumented)
-export class LegacyInternals implements ILegacyInternals {
-    constructor(uiExports: LegacyUiExports, config: LegacyConfig, server: Server);
-    // (undocumented)
-    getInjectedUiAppVars(id: string): Promise<Record<string, any>>;
-    // (undocumented)
-    getVars(id: string, request: KibanaRequest | LegacyRequest, injected?: LegacyVars): Promise<Record<string, any>>;
-    // Warning: (ae-forgotten-export) The symbol "VarsInjector" needs to be exported by the entry point index.d.ts
-    //
-    // (undocumented)
-    injectUiAppVars(id: string, injector: VarsInjector): void;
-    }
-
 // @public @deprecated (undocumented)
 export interface LegacyRequest extends Request {
 }
@@ -1312,16 +1293,6 @@ export class LegacyScopedClusterClient implements ILegacyScopedClusterClient {
     callAsInternalUser(endpoint: string, clientParams?: Record<string, any>, options?: LegacyCallAPIOptions): Promise<any>;
     }
 
-// Warning: (ae-forgotten-export) The symbol "LegacyPlugins" needs to be exported by the entry point index.d.ts
-//
-// @internal @deprecated (undocumented)
-export interface LegacyServiceDiscoverPlugins extends LegacyPlugins {
-    // (undocumented)
-    pluginExtendedConfig: LegacyConfig;
-    // (undocumented)
-    settings: LegacyVars;
-}
-
 // @public @deprecated (undocumented)
 export interface LegacyServiceSetupDeps {
     // Warning: (ae-forgotten-export) The symbol "LegacyCoreSetup" needs to be exported by the entry point index.d.ts
@@ -1346,31 +1317,6 @@ export interface LegacyServiceStartDeps {
     plugins: Record<string, unknown>;
 }
 
-// @internal @deprecated (undocumented)
-export interface LegacyUiExports {
-    // Warning: (ae-forgotten-export) The symbol "VarsProvider" needs to be exported by the entry point index.d.ts
-    //
-    // (undocumented)
-    defaultInjectedVarProviders?: VarsProvider[];
-    // Warning: (ae-forgotten-export) The symbol "VarsReplacer" needs to be exported by the entry point index.d.ts
-    //
-    // (undocumented)
-    injectedVarsReplacers?: VarsReplacer[];
-    // Warning: (ae-forgotten-export) The symbol "LegacyNavLinkSpec" needs to be exported by the entry point index.d.ts
-    //
-    // (undocumented)
-    navLinkSpecs?: LegacyNavLinkSpec[] | null;
-    // Warning: (ae-forgotten-export) The symbol "LegacyAppSpec" needs to be exported by the entry point index.d.ts
-    //
-    // (undocumented)
-    uiAppSpecs?: Array<LegacyAppSpec | undefined>;
-    // (undocumented)
-    unknown?: [{
-        pluginSpec: LegacyPluginSpec;
-        type: unknown;
-    }];
-}
-
 // Warning: (ae-forgotten-export) The symbol "lifecycleResponseFactory" needs to be exported by the entry point index.d.ts
 //
 // @public
@@ -2734,7 +2680,6 @@ export const validBodyOutput: readonly ["data", "stream"];
 // Warnings were encountered during analysis:
 //
 // src/core/server/http/router/response.ts:316:3 - (ae-forgotten-export) The symbol "KibanaResponse" needs to be exported by the entry point index.d.ts
-// src/core/server/legacy/types.ts:135:16 - (ae-forgotten-export) The symbol "LegacyPluginSpec" needs to be exported by the entry point index.d.ts
 // src/core/server/plugins/types.ts:274:3 - (ae-forgotten-export) The symbol "KibanaConfigType" needs to be exported by the entry point index.d.ts
 // src/core/server/plugins/types.ts:274:3 - (ae-forgotten-export) The symbol "SharedGlobalConfigKeys" needs to be exported by the entry point index.d.ts
 // src/core/server/plugins/types.ts:277:3 - (ae-forgotten-export) The symbol "SavedObjectsConfigType" needs to be exported by the entry point index.d.ts
diff --git a/src/core/server/server.ts b/src/core/server/server.ts
index 8502f563cb0c2..5935636d54f9d 100644
--- a/src/core/server/server.ts
+++ b/src/core/server/server.ts
@@ -113,11 +113,12 @@ export class Server {
     const { pluginTree, uiPlugins } = await this.plugins.discover({
       environment: environmentSetup,
     });
-    const legacyPlugins = await this.legacy.discoverPlugins();
+    const legacyConfigSetup = await this.legacy.setupLegacyConfig();
 
     // Immediately terminate in case of invalid configuration
+    // This needs to be done after plugin discovery
     await this.configService.validate();
-    await ensureValidConfiguration(this.configService, legacyPlugins);
+    await ensureValidConfiguration(this.configService, legacyConfigSetup);
 
     const contextServiceSetup = this.context.setup({
       // We inject a fake "legacy plugin" with dependencies on every plugin so that legacy plugins:
@@ -166,7 +167,6 @@ export class Server {
     const renderingSetup = await this.rendering.setup({
       http: httpSetup,
       status: statusSetup,
-      legacyPlugins,
       uiPlugins,
     });
 
@@ -248,10 +248,6 @@ export class Server {
 
     await this.http.start();
 
-    await this.rendering.start({
-      legacy: this.legacy,
-    });
-
     return this.coreStart;
   }
 
diff --git a/src/dev/jest/config.js b/src/dev/jest/config.js
index 498d953e386ff..a456c4b653337 100644
--- a/src/dev/jest/config.js
+++ b/src/dev/jest/config.js
@@ -52,7 +52,6 @@ export default {
     '@elastic/eui$': '<rootDir>/node_modules/@elastic/eui/test-env',
     '@elastic/eui/lib/(.*)?': '<rootDir>/node_modules/@elastic/eui/test-env/$1',
     '^src/plugins/(.*)': '<rootDir>/src/plugins/$1',
-    '^uiExports/(.*)': '<rootDir>/src/dev/jest/mocks/file_mock.js',
     '^test_utils/(.*)': '<rootDir>/src/test_utils/public/$1',
     '^fixtures/(.*)': '<rootDir>/src/fixtures/$1',
     '\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
diff --git a/src/legacy/plugin_discovery/README.md b/src/legacy/plugin_discovery/README.md
deleted file mode 100644
index 83e7c10d16fff..0000000000000
--- a/src/legacy/plugin_discovery/README.md
+++ /dev/null
@@ -1,148 +0,0 @@
-# Plugin Discovery
-
-The plugin discovery module defines the core plugin loading logic used by the Kibana server. It exports functions for
-
-
-## `findPluginSpecs(settings, [config])`
-
-Finds [`PluginSpec`][PluginSpec] objects
-
-### params
- - `settings`: the same settings object accepted by [`KbnServer`][KbnServer]
- - `[config]`: Optional - a [`Config`][Config] service. Using this param causes `findPluginSpecs()` to modify `config`'s schema to support the configuration for each discovered [`PluginSpec`][PluginSpec]. If you can, please use the [`Config`][Config] service produced by `extendedConfig$` rather than passing in an existing service so that `findPluginSpecs()` is side-effect free.
-
-### return value
-
-`findPluginSpecs()` returns an object of Observables which produce values at different parts of the process. Since the Observables are all aware of their own dependencies you can subscribe to any combination (within the same tick) and only the necessary plugin logic will be executed.
-
-If you *never* subscribe to any of the Observables then plugin discovery won't actually run.
-
- - `pack$`: emits every [`PluginPack`][PluginPack] found
- - `invalidDirectoryError$: Observable<Error>`: emits [`InvalidDirectoryError`][Errors]s caused by `settings.plugins.scanDirs` values that don't point to actual directories. `findPluginSpecs()` will not abort when this error is encountered.
- - `invalidPackError$: Observable<Error>`: emits [`InvalidPackError`][Errors]s caused by children of `settings.plugins.scanDirs` or `settings.plugins.paths` values which don't meet the requirements of a [`PluginPack`][PluginPack] (probably missing a `package.json`). `findPluginSpecs()` will not abort when this error is encountered.
- - `deprecation$: Observable<string>`: emits deprecation warnings that are produces when reading each [`PluginPack`][PluginPack]'s configuration
- - `extendedConfig$: Observable<Config>`: emits the [`Config`][Config] service that was passed to `findPluginSpecs()` (or created internally if none was passed) after it has been extended with the configuration from each plugin
- - `spec$: Observable<PluginSpec>`: emits every *enabled* [`PluginSpec`][PluginSpec] defined by the discovered [`PluginPack`][PluginPack]s
- - `disabledSpec$: Observable<PluginSpec>`: emits every *disabled* [`PluginSpec`][PluginSpec] defined by the discovered [`PluginPack`][PluginPack]s
- - `invalidVersionSpec$: Observable<PluginSpec>`: emits every [`PluginSpec`][PluginSpec] who's required kibana version does not match the version exposed by `config.get('pkg.version')`
-
-### example
-
-Just get the plugin specs, only fail if there is an uncaught error of some sort:
-```js
-const { pack$ } = findPluginSpecs(settings);
-const packs = await pack$.pipe(toArray()).toPromise()
-```
-
-Just log the deprecation messages:
-```js
-const { deprecation$ } = findPluginSpecs(settings);
-for (const warning of await deprecation$.pipe(toArray()).toPromise()) {
-  console.log('DEPRECATION:', warning)
-}
-```
-
-Get the packs but fail if any packs are invalid:
-```js
-const { pack$, invalidDirectoryError$ } = findPluginSpecs(settings);
-const packs = await Rx.merge(
-  pack$.pipe(toArray()),
-
-  // if we ever get an InvalidDirectoryError, throw it
-  // into the stream so that all streams are unsubscribed,
-  // the discovery process is aborted, and the promise rejects
-  invalidDirectoryError$.pipe(
-    map(error => { throw error })
-  ),
-).toPromise()
-```
-
-Handle everything
-```js
-const {
-  pack$,
-  invalidDirectoryError$,
-  invalidPackError$,
-  deprecation$,
-  extendedConfig$,
-  spec$,
-  disabledSpecs$,
-  invalidVersionSpec$,
-} = findPluginSpecs(settings);
-
-Rx.merge(
-  pack$.pipe(
-    tap(pluginPack => console.log('Found plugin pack', pluginPack))
-  ),
-
-  invalidDirectoryError$.pipe(
-    tap(error => console.log('Invalid directory error', error))
-  ),
-
-  invalidPackError$.pipe(
-    tap(error => console.log('Invalid plugin pack error', error))
-  ),
-
-  deprecation$.pipe(
-    tap(msg => console.log('DEPRECATION:', msg))
-  ),
-
-  extendedConfig$.pipe(
-    tap(config => console.log('config service extended by plugins', config))
-  ),
-
-  spec$.pipe(
-    tap(pluginSpec => console.log('enabled plugin spec found', spec))
-  ),
-
-  disabledSpec$.pipe(
-    tap(pluginSpec => console.log('disabled plugin spec found', spec))
-  ),
-
-  invalidVersionSpec$.pipe(
-    tap(pluginSpec => console.log('plugin spec with invalid version found', spec))
-  ),
-)
-.toPromise()
-.then(() => {
-  console.log('plugin discovery complete')
-})
-.catch((error) => {
-  console.log('plugin discovery failed', error)
-})
-
-```
-
-## `reduceExportSpecs(pluginSpecs, reducers, [defaults={}])`
-
-Reduces every value exported by the [`PluginSpec`][PluginSpec]s to produce a single value. If an exported value is an array each item in the array will be reduced individually. If the exported value is `undefined` it will be ignored. The reducer is called with the signature:
-
-```js
-reducer(
-  // the result of the previous reducer call, or `defaults`
-  acc: any,
-  // the exported value, found at `uiExports[type]` or `uiExports[type][i]`
-  // in the PluginSpec config.
-  spec: any,
-  // the key in `uiExports` where this export was found
-  type: string,
-  // the PluginSpec which exported this spec
-  pluginSpec: PluginSpec
-)
-```
-
-## `new PluginPack(options)` class
-
-Only exported so that `PluginPack` instances can be created in tests and used in place of on-disk plugin fixtures. Use `findPluginSpecs()`, or the cached result of a call to `findPluginSpecs()` (like `kbnServer.pluginSpecs`) any time you might need access to `PluginPack` objects in distributed code.
-
-### params
-
- - `options.path`: absolute path to where this plugin pack was found, this is normally a direct child of `./src/legacy/core_plugins` or `./plugins`
- - `options.pkg`: the parsed `package.json` for this pack, used for defaults in `PluginSpec` objects defined by this pack
- - `options.provider`: the default export of the pack, a function which is called with the `PluginSpec` class which should return one or more `PluginSpec` objects.
-
-[PluginPack]: ./plugin_pack/plugin_pack.js "PluginPath class definition"
-[PluginSpec]: ./plugin_spec/plugin_spec.js "PluginSpec class definition"
-[Errors]: ./errors.js "PluginDiscover specific error types"
-[KbnServer]: ../server/kbn_server.js "KbnServer class definition"
-[Config]: ../server/config/config.js "KbnServer/Config class definition"
diff --git a/src/legacy/plugin_discovery/__tests__/find_plugin_specs.js b/src/legacy/plugin_discovery/__tests__/find_plugin_specs.js
deleted file mode 100644
index e6af23d69c549..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/find_plugin_specs.js
+++ /dev/null
@@ -1,219 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve } from 'path';
-import { toArray } from 'rxjs/operators';
-
-import expect from '@kbn/expect';
-import { isEqual } from 'lodash';
-import { findPluginSpecs } from '../find_plugin_specs';
-import { PluginSpec } from '../plugin_spec';
-
-const PLUGIN_FIXTURES = resolve(__dirname, 'fixtures/plugins');
-const CONFLICT_FIXTURES = resolve(__dirname, 'fixtures/conflicts');
-
-describe('plugin discovery', () => {
-  describe('findPluginSpecs()', function () {
-    this.timeout(10000);
-
-    describe('spec$', () => {
-      it('finds specs for specified plugin paths', async () => {
-        const { spec$ } = findPluginSpecs({
-          plugins: {
-            paths: [
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-            ],
-          },
-        });
-
-        const specs = await spec$.pipe(toArray()).toPromise();
-        expect(specs).to.have.length(3);
-        specs.forEach((spec) => {
-          expect(spec).to.be.a(PluginSpec);
-        });
-        expect(specs.map((s) => s.getId()).sort()).to.eql(['bar:one', 'bar:two', 'foo']);
-      });
-
-      it('finds all specs in scanDirs', async () => {
-        const { spec$ } = findPluginSpecs({
-          // used to ensure the dev_mode plugin is enabled
-          env: 'development',
-
-          plugins: {
-            scanDirs: [PLUGIN_FIXTURES],
-          },
-        });
-
-        const specs = await spec$.pipe(toArray()).toPromise();
-        expect(specs).to.have.length(3);
-        specs.forEach((spec) => {
-          expect(spec).to.be.a(PluginSpec);
-        });
-        expect(specs.map((s) => s.getId()).sort()).to.eql(['bar:one', 'bar:two', 'foo']);
-      });
-
-      it('does not find disabled plugins', async () => {
-        const { spec$ } = findPluginSpecs({
-          'bar:one': {
-            enabled: false,
-          },
-
-          plugins: {
-            paths: [
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-            ],
-          },
-        });
-
-        const specs = await spec$.pipe(toArray()).toPromise();
-        expect(specs).to.have.length(2);
-        specs.forEach((spec) => {
-          expect(spec).to.be.a(PluginSpec);
-        });
-        expect(specs.map((s) => s.getId()).sort()).to.eql(['bar:two', 'foo']);
-      });
-
-      it('dedupes duplicate packs', async () => {
-        const { spec$ } = findPluginSpecs({
-          plugins: {
-            scanDirs: [PLUGIN_FIXTURES],
-            paths: [
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-            ],
-          },
-        });
-
-        const specs = await spec$.pipe(toArray()).toPromise();
-        expect(specs).to.have.length(3);
-        specs.forEach((spec) => {
-          expect(spec).to.be.a(PluginSpec);
-        });
-        expect(specs.map((s) => s.getId()).sort()).to.eql(['bar:one', 'bar:two', 'foo']);
-      });
-
-      describe('conflicting plugin spec ids', () => {
-        it('fails with informative message', async () => {
-          const { spec$ } = findPluginSpecs({
-            plugins: {
-              scanDirs: [],
-              paths: [resolve(CONFLICT_FIXTURES, 'foo')],
-            },
-          });
-
-          try {
-            await spec$.pipe(toArray()).toPromise();
-            throw new Error('expected spec$ to throw an error');
-          } catch (error) {
-            expect(error.message).to.contain('Multiple plugins found with the id "foo"');
-            expect(error.message).to.contain(CONFLICT_FIXTURES);
-          }
-        });
-      });
-    });
-
-    describe('packageJson$', () => {
-      const checkPackageJsons = (packageJsons) => {
-        expect(packageJsons).to.have.length(2);
-        const package1 = packageJsons.find((packageJson) =>
-          isEqual(
-            {
-              directoryPath: resolve(PLUGIN_FIXTURES, 'foo'),
-              contents: {
-                name: 'foo',
-                version: 'kibana',
-              },
-            },
-            packageJson
-          )
-        );
-        expect(package1).to.be.an(Object);
-        const package2 = packageJsons.find((packageJson) =>
-          isEqual(
-            {
-              directoryPath: resolve(PLUGIN_FIXTURES, 'bar'),
-              contents: {
-                name: 'foo',
-                version: 'kibana',
-              },
-            },
-            packageJson
-          )
-        );
-        expect(package2).to.be.an(Object);
-      };
-
-      it('finds packageJson for specified plugin paths', async () => {
-        const { packageJson$ } = findPluginSpecs({
-          plugins: {
-            paths: [
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-            ],
-          },
-        });
-
-        const packageJsons = await packageJson$.pipe(toArray()).toPromise();
-        checkPackageJsons(packageJsons);
-      });
-
-      it('finds all packageJsons in scanDirs', async () => {
-        const { packageJson$ } = findPluginSpecs({
-          // used to ensure the dev_mode plugin is enabled
-          env: 'development',
-
-          plugins: {
-            scanDirs: [PLUGIN_FIXTURES],
-          },
-        });
-
-        const packageJsons = await packageJson$.pipe(toArray()).toPromise();
-        checkPackageJsons(packageJsons);
-      });
-
-      it('dedupes duplicate packageJson', async () => {
-        const { packageJson$ } = findPluginSpecs({
-          plugins: {
-            scanDirs: [PLUGIN_FIXTURES],
-            paths: [
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'foo'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'bar'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-              resolve(PLUGIN_FIXTURES, 'broken'),
-            ],
-          },
-        });
-
-        const packageJsons = await packageJson$.pipe(toArray()).toPromise();
-        checkPackageJsons(packageJsons);
-      });
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/conflicts/foo/index.js b/src/legacy/plugin_discovery/__tests__/fixtures/conflicts/foo/index.js
deleted file mode 100644
index fcbe3487463b7..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/conflicts/foo/index.js
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default function (kibana) {
-  return [
-    // two plugins exported without ids will both inherit
-    // the id of the pack and conflict
-    new kibana.Plugin({}),
-    new kibana.Plugin({}),
-  ];
-}
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/conflicts/foo/package.json b/src/legacy/plugin_discovery/__tests__/fixtures/conflicts/foo/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/conflicts/foo/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/bar/index.js b/src/legacy/plugin_discovery/__tests__/fixtures/plugins/bar/index.js
deleted file mode 100644
index 0eef126f2255a..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/bar/index.js
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default function (kibana) {
-  return [
-    new kibana.Plugin({
-      id: 'bar:one',
-    }),
-    new kibana.Plugin({
-      id: 'bar:two',
-    }),
-  ];
-}
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/bar/package.json b/src/legacy/plugin_discovery/__tests__/fixtures/plugins/bar/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/bar/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/broken/index.js b/src/legacy/plugin_discovery/__tests__/fixtures/plugins/broken/index.js
deleted file mode 100644
index 59f4a2649f019..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/broken/index.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default {
-  foo: 'bar',
-};
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/broken/package1.json b/src/legacy/plugin_discovery/__tests__/fixtures/plugins/broken/package1.json
deleted file mode 100644
index 81ddb6221d515..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/broken/package1.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "baz",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/foo/index.js b/src/legacy/plugin_discovery/__tests__/fixtures/plugins/foo/index.js
deleted file mode 100644
index e43a1dcedb372..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/foo/index.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-module.exports = function (kibana) {
-  return new kibana.Plugin({
-    id: 'foo',
-  });
-};
diff --git a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/foo/package.json b/src/legacy/plugin_discovery/__tests__/fixtures/plugins/foo/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/__tests__/fixtures/plugins/foo/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/errors.js b/src/legacy/plugin_discovery/errors.js
deleted file mode 100644
index 02d81b32d1fd1..0000000000000
--- a/src/legacy/plugin_discovery/errors.js
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-const errorCodeProperty = Symbol('pluginDiscovery/errorCode');
-
-/**
- *  Thrown when reading a plugin directory fails, wraps failure
- *  @type {String}
- */
-const ERROR_INVALID_DIRECTORY = 'ERROR_INVALID_DIRECTORY';
-export function createInvalidDirectoryError(sourceError, path) {
-  sourceError[errorCodeProperty] = ERROR_INVALID_DIRECTORY;
-  sourceError.path = path;
-  return sourceError;
-}
-export function isInvalidDirectoryError(error) {
-  return error && error[errorCodeProperty] === ERROR_INVALID_DIRECTORY;
-}
-
-/**
- *  Thrown when trying to create a PluginPack for a path that
- *  is not a valid plugin definition
- *  @type {String}
- */
-const ERROR_INVALID_PACK = 'ERROR_INVALID_PACK';
-export function createInvalidPackError(path, reason) {
-  const error = new Error(`PluginPack${path ? ` at "${path}"` : ''} ${reason}`);
-  error[errorCodeProperty] = ERROR_INVALID_PACK;
-  error.path = path;
-  return error;
-}
-export function isInvalidPackError(error) {
-  return error && error[errorCodeProperty] === ERROR_INVALID_PACK;
-}
-
-/**
- *  Thrown when trying to load a PluginSpec that is invalid for some reason
- *  @type {String}
- */
-const ERROR_INVALID_PLUGIN = 'ERROR_INVALID_PLUGIN';
-export function createInvalidPluginError(spec, reason) {
-  const error = new Error(
-    `Plugin from ${spec.getId()} at ${spec.getPack().getPath()} is invalid because ${reason}`
-  );
-  error[errorCodeProperty] = ERROR_INVALID_PLUGIN;
-  error.spec = spec;
-  return error;
-}
-export function isInvalidPluginError(error) {
-  return error && error[errorCodeProperty] === ERROR_INVALID_PLUGIN;
-}
-
-/**
- *  Thrown when trying to load a PluginSpec whose version is incompatible
- *  @type {String}
- */
-const ERROR_INCOMPATIBLE_PLUGIN_VERSION = 'ERROR_INCOMPATIBLE_PLUGIN_VERSION';
-export function createIncompatiblePluginVersionError(spec) {
-  const error = new Error(
-    `Plugin ${spec.getId()} is only compatible with Kibana version ${spec.getExpectedKibanaVersion()}`
-  );
-  error[errorCodeProperty] = ERROR_INCOMPATIBLE_PLUGIN_VERSION;
-  error.spec = spec;
-  return error;
-}
-export function isIncompatiblePluginVersionError(error) {
-  return error && error[errorCodeProperty] === ERROR_INCOMPATIBLE_PLUGIN_VERSION;
-}
diff --git a/src/legacy/plugin_discovery/find_plugin_specs.js b/src/legacy/plugin_discovery/find_plugin_specs.js
deleted file mode 100644
index b97476bb456a5..0000000000000
--- a/src/legacy/plugin_discovery/find_plugin_specs.js
+++ /dev/null
@@ -1,234 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import * as Rx from 'rxjs';
-import {
-  distinct,
-  toArray,
-  mergeMap,
-  share,
-  shareReplay,
-  filter,
-  last,
-  map,
-  tap,
-} from 'rxjs/operators';
-import { realpathSync } from 'fs';
-
-import { Config } from '../server/config';
-
-import { extendConfigService, disableConfigExtension } from './plugin_config';
-
-import {
-  createPack$,
-  createPackageJsonAtPath$,
-  createPackageJsonsInDirectory$,
-} from './plugin_pack';
-
-import { isInvalidDirectoryError, isInvalidPackError } from './errors';
-
-export function defaultConfig(settings) {
-  return Config.withDefaultSchema(settings);
-}
-
-function bufferAllResults(observable) {
-  return observable.pipe(
-    // buffer all results into a single array
-    toArray(),
-    // merge the array back into the stream when complete
-    mergeMap((array) => array)
-  );
-}
-
-/**
- * Determine a distinct value for each result from find$
- * so they can be deduplicated
- * @param  {{error?,pack?}} result
- * @return {Any}
- */
-function getDistinctKeyForFindResult(result) {
-  // errors are distinct by their message
-  if (result.error) {
-    return result.error.message;
-  }
-
-  // packs are distinct by their absolute and real path
-  if (result.packageJson) {
-    return realpathSync(result.packageJson.directoryPath);
-  }
-
-  // non error/pack results shouldn't exist, but if they do they are all unique
-  return result;
-}
-
-function groupSpecsById(specs) {
-  const specsById = new Map();
-  for (const spec of specs) {
-    const id = spec.getId();
-    if (specsById.has(id)) {
-      specsById.get(id).push(spec);
-    } else {
-      specsById.set(id, [spec]);
-    }
-  }
-  return specsById;
-}
-
-/**
- *  Creates a collection of observables for discovering pluginSpecs
- *  using Kibana's defaults, settings, and config service
- *
- *  @param {Object} settings
- *  @param {ConfigService} [configToMutate] when supplied **it is mutated** to
- *  include the config from discovered plugin specs
- *  @return {Object<name,Rx>}
- */
-export function findPluginSpecs(settings, configToMutate) {
-  const config$ = Rx.defer(async () => {
-    if (configToMutate) {
-      return configToMutate;
-    }
-
-    return defaultConfig(settings);
-  }).pipe(shareReplay());
-
-  // find plugin packs in configured paths/dirs
-  const packageJson$ = config$.pipe(
-    mergeMap((config) =>
-      Rx.merge(
-        ...config.get('plugins.paths').map(createPackageJsonAtPath$),
-        ...config.get('plugins.scanDirs').map(createPackageJsonsInDirectory$)
-      )
-    ),
-    distinct(getDistinctKeyForFindResult),
-    share()
-  );
-
-  const pack$ = createPack$(packageJson$).pipe(share());
-
-  const extendConfig$ = config$.pipe(
-    mergeMap((config) =>
-      pack$.pipe(
-        // get the specs for each found plugin pack
-        mergeMap(({ pack }) => (pack ? pack.getPluginSpecs() : [])),
-        // make sure that none of the plugin specs have conflicting ids, fail
-        // early if conflicts detected or merge the specs back into the stream
-        toArray(),
-        mergeMap((allSpecs) => {
-          for (const [id, specs] of groupSpecsById(allSpecs)) {
-            if (specs.length > 1) {
-              throw new Error(
-                `Multiple plugins found with the id "${id}":\n${specs
-                  .map((spec) => `  - ${id} at ${spec.getPath()}`)
-                  .join('\n')}`
-              );
-            }
-          }
-
-          return allSpecs;
-        }),
-        mergeMap(async (spec) => {
-          // extend the config service with this plugin spec and
-          // collect its deprecations messages if some of its
-          // settings are outdated
-          const deprecations = [];
-          await extendConfigService(spec, config, settings, (message) => {
-            deprecations.push({ spec, message });
-          });
-
-          return {
-            spec,
-            deprecations,
-          };
-        }),
-        // extend the config with all plugins before determining enabled status
-        bufferAllResults,
-        map(({ spec, deprecations }) => {
-          const isRightVersion = spec.isVersionCompatible(config.get('pkg.version'));
-          const enabled = isRightVersion && spec.isEnabled(config);
-          return {
-            config,
-            spec,
-            deprecations,
-            enabledSpecs: enabled ? [spec] : [],
-            disabledSpecs: enabled ? [] : [spec],
-            invalidVersionSpecs: isRightVersion ? [] : [spec],
-          };
-        }),
-        // determine which plugins are disabled before actually removing things from the config
-        bufferAllResults,
-        tap((result) => {
-          for (const spec of result.disabledSpecs) {
-            disableConfigExtension(spec, config);
-          }
-        })
-      )
-    ),
-    share()
-  );
-
-  return {
-    // package JSONs found when searching configure paths
-    packageJson$: packageJson$.pipe(
-      mergeMap((result) => (result.packageJson ? [result.packageJson] : []))
-    ),
-
-    // plugin packs found when searching configured paths
-    pack$: pack$.pipe(mergeMap((result) => (result.pack ? [result.pack] : []))),
-
-    // errors caused by invalid directories of plugin directories
-    invalidDirectoryError$: pack$.pipe(
-      mergeMap((result) => (isInvalidDirectoryError(result.error) ? [result.error] : []))
-    ),
-
-    // errors caused by directories that we expected to be plugin but were invalid
-    invalidPackError$: pack$.pipe(
-      mergeMap((result) => (isInvalidPackError(result.error) ? [result.error] : []))
-    ),
-
-    otherError$: pack$.pipe(
-      mergeMap((result) => (isUnhandledError(result.error) ? [result.error] : []))
-    ),
-
-    // { spec, message } objects produced when transforming deprecated
-    // settings for a plugin spec
-    deprecation$: extendConfig$.pipe(mergeMap((result) => result.deprecations)),
-
-    // the config service we extended with all of the plugin specs,
-    // only emitted once it is fully extended by all
-    extendedConfig$: extendConfig$.pipe(
-      mergeMap((result) => result.config),
-      filter(Boolean),
-      last()
-    ),
-
-    // all enabled PluginSpec objects
-    spec$: extendConfig$.pipe(mergeMap((result) => result.enabledSpecs)),
-
-    // all disabled PluginSpec objects
-    disabledSpec$: extendConfig$.pipe(mergeMap((result) => result.disabledSpecs)),
-
-    // all PluginSpec objects that were disabled because their version was incompatible
-    invalidVersionSpec$: extendConfig$.pipe(mergeMap((result) => result.invalidVersionSpecs)),
-  };
-}
-
-function isUnhandledError(error) {
-  return error != null && !isInvalidDirectoryError(error) && !isInvalidPackError(error);
-}
diff --git a/src/legacy/plugin_discovery/index.js b/src/legacy/plugin_discovery/index.js
deleted file mode 100644
index b60806f6cbc23..0000000000000
--- a/src/legacy/plugin_discovery/index.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { findPluginSpecs } from './find_plugin_specs';
-export { reduceExportSpecs } from './plugin_exports';
-export { PluginPack } from './plugin_pack';
diff --git a/src/legacy/plugin_discovery/plugin_config/__tests__/extend_config_service.js b/src/legacy/plugin_discovery/plugin_config/__tests__/extend_config_service.js
deleted file mode 100644
index 40f84f6f54b3b..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/__tests__/extend_config_service.js
+++ /dev/null
@@ -1,162 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import sinon from 'sinon';
-import expect from '@kbn/expect';
-
-import { Config } from '../../../server/config';
-import { PluginPack } from '../../plugin_pack';
-import { extendConfigService, disableConfigExtension } from '../extend_config_service';
-import * as SchemaNS from '../schema';
-import * as SettingsNS from '../settings';
-
-describe('plugin discovery/extend config service', () => {
-  const sandbox = sinon.createSandbox();
-  afterEach(() => sandbox.restore());
-
-  const pluginSpec = new PluginPack({
-    path: '/dev/null',
-    pkg: {
-      name: 'test',
-      version: 'kibana',
-    },
-    provider: ({ Plugin }) =>
-      new Plugin({
-        configPrefix: 'foo.bar.baz',
-
-        config: (Joi) =>
-          Joi.object({
-            enabled: Joi.boolean().default(true),
-            test: Joi.string().default('bonk'),
-          }).default(),
-      }),
-  })
-    .getPluginSpecs()
-    .pop();
-
-  describe('extendConfigService()', () => {
-    it('calls getSettings, getSchema, and Config.extendSchema() correctly', async () => {
-      const rootSettings = {
-        foo: {
-          bar: {
-            enabled: false,
-          },
-        },
-      };
-      const schema = {
-        validate: () => {},
-      };
-      const configPrefix = 'foo.bar';
-      const config = {
-        extendSchema: sandbox.stub(),
-      };
-      const pluginSpec = {
-        getConfigPrefix: sandbox.stub().returns(configPrefix),
-      };
-
-      const getSettings = sandbox.stub(SettingsNS, 'getSettings').returns(rootSettings.foo.bar);
-
-      const getSchema = sandbox.stub(SchemaNS, 'getSchema').returns(schema);
-
-      await extendConfigService(pluginSpec, config, rootSettings);
-
-      sinon.assert.calledOnce(getSettings);
-      sinon.assert.calledWithExactly(getSettings, pluginSpec, rootSettings);
-
-      sinon.assert.calledOnce(getSchema);
-      sinon.assert.calledWithExactly(getSchema, pluginSpec);
-
-      sinon.assert.calledOnce(config.extendSchema);
-      sinon.assert.calledWithExactly(
-        config.extendSchema,
-        schema,
-        rootSettings.foo.bar,
-        configPrefix
-      );
-    });
-
-    it('adds the schema for a plugin spec to its config prefix', async () => {
-      const config = Config.withDefaultSchema();
-      expect(config.has('foo.bar.baz')).to.be(false);
-      await extendConfigService(pluginSpec, config);
-      expect(config.has('foo.bar.baz')).to.be(true);
-    });
-
-    it('initializes it with the default settings', async () => {
-      const config = Config.withDefaultSchema();
-      await extendConfigService(pluginSpec, config);
-      expect(config.get('foo.bar.baz.enabled')).to.be(true);
-      expect(config.get('foo.bar.baz.test')).to.be('bonk');
-    });
-
-    it('initializes it with values from root settings if defined', async () => {
-      const config = Config.withDefaultSchema();
-      await extendConfigService(pluginSpec, config, {
-        foo: {
-          bar: {
-            baz: {
-              test: 'hello world',
-            },
-          },
-        },
-      });
-
-      expect(config.get('foo.bar.baz.test')).to.be('hello world');
-    });
-
-    it('throws if root settings are invalid', async () => {
-      const config = Config.withDefaultSchema();
-      try {
-        await extendConfigService(pluginSpec, config, {
-          foo: {
-            bar: {
-              baz: {
-                test: {
-                  'not a string': true,
-                },
-              },
-            },
-          },
-        });
-        throw new Error('Expected extendConfigService() to throw because of bad settings');
-      } catch (error) {
-        expect(error.message).to.contain('"test" must be a string');
-      }
-    });
-  });
-
-  describe('disableConfigExtension()', () => {
-    it('removes added config', async () => {
-      const config = Config.withDefaultSchema();
-      await extendConfigService(pluginSpec, config);
-      expect(config.has('foo.bar.baz.test')).to.be(true);
-      await disableConfigExtension(pluginSpec, config);
-      expect(config.has('foo.bar.baz.test')).to.be(false);
-    });
-
-    it('leaves {configPrefix}.enabled config', async () => {
-      const config = Config.withDefaultSchema();
-      expect(config.has('foo.bar.baz.enabled')).to.be(false);
-      await extendConfigService(pluginSpec, config);
-      expect(config.get('foo.bar.baz.enabled')).to.be(true);
-      await disableConfigExtension(pluginSpec, config);
-      expect(config.get('foo.bar.baz.enabled')).to.be(false);
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_config/__tests__/schema.js b/src/legacy/plugin_discovery/plugin_config/__tests__/schema.js
deleted file mode 100644
index 78adb1e680e20..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/__tests__/schema.js
+++ /dev/null
@@ -1,92 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import expect from '@kbn/expect';
-
-import { PluginPack } from '../../plugin_pack';
-import { getSchema, getStubSchema } from '../schema';
-
-describe('plugin discovery/schema', () => {
-  function createPluginSpec(configProvider) {
-    return new PluginPack({
-      path: '/dev/null',
-      pkg: {
-        name: 'test',
-        version: 'kibana',
-      },
-      provider: ({ Plugin }) =>
-        new Plugin({
-          configPrefix: 'foo.bar.baz',
-          config: configProvider,
-        }),
-    })
-      .getPluginSpecs()
-      .pop();
-  }
-
-  describe('getSchema()', () => {
-    it('calls the config provider and returns its return value', async () => {
-      const pluginSpec = createPluginSpec(() => 'foo');
-      expect(await getSchema(pluginSpec)).to.be('foo');
-    });
-
-    it('supports config provider that returns a promise', async () => {
-      const pluginSpec = createPluginSpec(() => Promise.resolve('foo'));
-      expect(await getSchema(pluginSpec)).to.be('foo');
-    });
-
-    it('uses default schema when no config provider', async () => {
-      const schema = await getSchema(createPluginSpec());
-      expect(schema).to.be.an('object');
-      expect(schema).to.have.property('validate').a('function');
-      expect(schema.validate({}).value).to.eql({
-        enabled: true,
-      });
-    });
-
-    it('uses default schema when config returns falsy value', async () => {
-      const schema = await getSchema(createPluginSpec(() => null));
-      expect(schema).to.be.an('object');
-      expect(schema).to.have.property('validate').a('function');
-      expect(schema.validate({}).value).to.eql({
-        enabled: true,
-      });
-    });
-
-    it('uses default schema when config promise resolves to falsy value', async () => {
-      const schema = await getSchema(createPluginSpec(() => Promise.resolve(null)));
-      expect(schema).to.be.an('object');
-      expect(schema).to.have.property('validate').a('function');
-      expect(schema.validate({}).value).to.eql({
-        enabled: true,
-      });
-    });
-  });
-
-  describe('getStubSchema()', () => {
-    it('returns schema with enabled: false', async () => {
-      const schema = await getStubSchema();
-      expect(schema).to.be.an('object');
-      expect(schema).to.have.property('validate').a('function');
-      expect(schema.validate({}).value).to.eql({
-        enabled: false,
-      });
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_config/__tests__/settings.js b/src/legacy/plugin_discovery/plugin_config/__tests__/settings.js
deleted file mode 100644
index 750c5ee6c6f50..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/__tests__/settings.js
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import expect from '@kbn/expect';
-
-import { PluginPack } from '../../plugin_pack';
-import { getSettings } from '../settings';
-
-describe('plugin_discovery/settings', () => {
-  const pluginSpec = new PluginPack({
-    path: '/dev/null',
-    pkg: {
-      name: 'test',
-      version: 'kibana',
-    },
-    provider: ({ Plugin }) =>
-      new Plugin({
-        configPrefix: 'a.b.c',
-      }),
-  })
-    .getPluginSpecs()
-    .pop();
-
-  describe('getSettings()', () => {
-    it('reads settings from config prefix', async () => {
-      const rootSettings = {
-        a: {
-          b: {
-            c: {
-              enabled: false,
-            },
-          },
-        },
-      };
-
-      expect(await getSettings(pluginSpec, rootSettings)).to.eql({
-        enabled: false,
-      });
-    });
-
-    it('allows rootSettings to be undefined', async () => {
-      expect(await getSettings(pluginSpec)).to.eql(undefined);
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_config/extend_config_service.js b/src/legacy/plugin_discovery/plugin_config/extend_config_service.js
deleted file mode 100644
index a6d5d4ae5f990..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/extend_config_service.js
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { getSettings } from './settings';
-import { getSchema, getStubSchema } from './schema';
-
-/**
- *  Extend a config service with the schema and settings for a
- *  plugin spec and optionally call logDeprecation with warning
- *  messages about deprecated settings that are used
- *  @param  {PluginSpec} spec
- *  @param  {Server.Config} config
- *  @param  {Object} rootSettings
- *  @param  {Function} [logDeprecation]
- *  @return {Promise<undefined>}
- */
-export async function extendConfigService(spec, config, rootSettings) {
-  const settings = await getSettings(spec, rootSettings);
-  const schema = await getSchema(spec);
-  config.extendSchema(schema, settings, spec.getConfigPrefix());
-}
-
-/**
- *  Disable the schema and settings applied to a config service for
- *  a plugin spec
- *  @param  {PluginSpec} spec
- *  @param  {Server.Config} config
- *  @return {undefined}
- */
-export function disableConfigExtension(spec, config) {
-  const prefix = spec.getConfigPrefix();
-  config.removeSchema(prefix);
-  config.extendSchema(getStubSchema(), { enabled: false }, prefix);
-}
diff --git a/src/legacy/plugin_discovery/plugin_config/index.js b/src/legacy/plugin_discovery/plugin_config/index.js
deleted file mode 100644
index a27463bc9c7f5..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { extendConfigService, disableConfigExtension } from './extend_config_service';
diff --git a/src/legacy/plugin_discovery/plugin_config/schema.js b/src/legacy/plugin_discovery/plugin_config/schema.js
deleted file mode 100644
index 14d10aa5568da..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/schema.js
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import Joi from 'joi';
-
-const STUB_CONFIG_SCHEMA = Joi.object()
-  .keys({
-    enabled: Joi.valid(false).default(false),
-  })
-  .default();
-
-const DEFAULT_CONFIG_SCHEMA = Joi.object()
-  .keys({
-    enabled: Joi.boolean().default(true),
-  })
-  .default();
-
-/**
- *  Get the config schema for a plugin spec
- *  @param  {PluginSpec} spec
- *  @return {Promise<Joi>}
- */
-export async function getSchema(spec) {
-  const provider = spec.getConfigSchemaProvider();
-  return (provider && (await provider(Joi))) || DEFAULT_CONFIG_SCHEMA;
-}
-
-export function getStubSchema() {
-  return STUB_CONFIG_SCHEMA;
-}
diff --git a/src/legacy/plugin_discovery/plugin_config/settings.js b/src/legacy/plugin_discovery/plugin_config/settings.js
deleted file mode 100644
index e6a4741d76eca..0000000000000
--- a/src/legacy/plugin_discovery/plugin_config/settings.js
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { get } from 'lodash';
-
-/**
- *  Get the settings for a pluginSpec from the raw root settings while
- *  optionally calling logDeprecation() with warnings about deprecated
- *  settings that were used
- *  @param  {PluginSpec} spec
- *  @param  {Object} rootSettings
- *  @return {Promise<Object>}
- */
-export async function getSettings(spec, rootSettings) {
-  const prefix = spec.getConfigPrefix();
-  const rawSettings = get(rootSettings, prefix);
-  return rawSettings;
-}
diff --git a/src/legacy/plugin_discovery/plugin_exports/__tests__/reduce_export_specs.js b/src/legacy/plugin_discovery/plugin_exports/__tests__/reduce_export_specs.js
deleted file mode 100644
index 3beaacc1a8293..0000000000000
--- a/src/legacy/plugin_discovery/plugin_exports/__tests__/reduce_export_specs.js
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import expect from '@kbn/expect';
-
-import { PluginPack } from '../../plugin_pack';
-import { reduceExportSpecs } from '../reduce_export_specs';
-
-const PLUGIN = new PluginPack({
-  path: __dirname,
-  pkg: {
-    name: 'foo',
-    version: 'kibana',
-  },
-  provider: ({ Plugin }) =>
-    new Plugin({
-      uiExports: {
-        concatNames: {
-          name: 'export1',
-        },
-
-        concat: ['export2', 'export3'],
-      },
-    }),
-});
-
-const REDUCERS = {
-  concatNames(acc, spec, type, pluginSpec) {
-    return {
-      names: [].concat(acc.names || [], `${pluginSpec.getId()}:${spec.name}`),
-    };
-  },
-  concat(acc, spec, type, pluginSpec) {
-    return {
-      names: [].concat(acc.names || [], `${pluginSpec.getId()}:${spec}`),
-    };
-  },
-};
-
-const PLUGIN_SPECS = PLUGIN.getPluginSpecs();
-
-describe('reduceExportSpecs', () => {
-  it('combines ui exports from a list of plugin definitions', () => {
-    const exports = reduceExportSpecs(PLUGIN_SPECS, REDUCERS);
-    expect(exports).to.eql({
-      names: ['foo:export1', 'foo:export2', 'foo:export3'],
-    });
-  });
-
-  it('starts with the defaults', () => {
-    const exports = reduceExportSpecs(PLUGIN_SPECS, REDUCERS, {
-      names: ['default'],
-    });
-
-    expect(exports).to.eql({
-      names: ['default', 'foo:export1', 'foo:export2', 'foo:export3'],
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_exports/index.js b/src/legacy/plugin_discovery/plugin_exports/index.js
deleted file mode 100644
index 0e3511ea85dd4..0000000000000
--- a/src/legacy/plugin_discovery/plugin_exports/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { reduceExportSpecs } from './reduce_export_specs';
diff --git a/src/legacy/plugin_discovery/plugin_exports/reduce_export_specs.js b/src/legacy/plugin_discovery/plugin_exports/reduce_export_specs.js
deleted file mode 100644
index a3adc3091085d..0000000000000
--- a/src/legacy/plugin_discovery/plugin_exports/reduce_export_specs.js
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- *  Combine the exportSpecs from a list of pluginSpecs
- *  by calling the reducers for each export type
- *  @param {Array<PluginSpecs>} pluginSpecs
- *  @param {Object<exportType,reducer>} reducers
- *  @param {Object<exportType,exports>} [defaults={}]
- *  @return {Object<exportType,exports>}
- */
-export function reduceExportSpecs(pluginSpecs, reducers, defaults = {}) {
-  return pluginSpecs.reduce((acc, pluginSpec) => {
-    const specsByType = pluginSpec.getExportSpecs() || {};
-    const types = Object.keys(specsByType);
-
-    return types.reduce((acc, type) => {
-      const reducer = reducers[type] || reducers.unknown;
-
-      if (!reducer) {
-        throw new Error(`Unknown export type ${type}`);
-      }
-
-      // convert specs to an array if not already one or
-      // ignore the spec if it is undefined
-      const specs = [].concat(specsByType[type] === undefined ? [] : specsByType[type]);
-
-      return specs.reduce((acc, spec) => reducer(acc, spec, type, pluginSpec), acc);
-    }, acc);
-  }, defaults);
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/create_pack.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/create_pack.js
deleted file mode 100644
index b17bd69479ffa..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/create_pack.js
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve } from 'path';
-import * as Rx from 'rxjs';
-import { toArray } from 'rxjs/operators';
-import expect from '@kbn/expect';
-
-import { createPack$ } from '../create_pack';
-import { PluginPack } from '../plugin_pack';
-
-import { PLUGINS_DIR, assertInvalidPackError } from './utils';
-
-describe('plugin discovery/create pack', () => {
-  it('creates PluginPack', async () => {
-    const packageJson$ = Rx.from([
-      {
-        packageJson: {
-          directoryPath: resolve(PLUGINS_DIR, 'prebuilt'),
-          contents: {
-            name: 'prebuilt',
-          },
-        },
-      },
-    ]);
-    const results = await createPack$(packageJson$).pipe(toArray()).toPromise();
-    expect(results).to.have.length(1);
-    expect(results[0]).to.only.have.keys(['pack']);
-    const { pack } = results[0];
-    expect(pack).to.be.a(PluginPack);
-  });
-
-  describe('errors thrown', () => {
-    async function checkError(path, check) {
-      const packageJson$ = Rx.from([
-        {
-          packageJson: {
-            directoryPath: path,
-          },
-        },
-      ]);
-
-      const results = await createPack$(packageJson$).pipe(toArray()).toPromise();
-      expect(results).to.have.length(1);
-      expect(results[0]).to.only.have.keys(['error']);
-      const { error } = results[0];
-      await check(error);
-    }
-    it('default export is an object', () =>
-      checkError(resolve(PLUGINS_DIR, 'exports_object'), (error) => {
-        assertInvalidPackError(error);
-        expect(error.message).to.contain('must export a function');
-      }));
-    it('default export is an number', () =>
-      checkError(resolve(PLUGINS_DIR, 'exports_number'), (error) => {
-        assertInvalidPackError(error);
-        expect(error.message).to.contain('must export a function');
-      }));
-    it('default export is an string', () =>
-      checkError(resolve(PLUGINS_DIR, 'exports_string'), (error) => {
-        assertInvalidPackError(error);
-        expect(error.message).to.contain('must export a function');
-      }));
-    it('directory with code that fails when required', () =>
-      checkError(resolve(PLUGINS_DIR, 'broken_code'), (error) => {
-        expect(error.message).to.contain("Cannot find module 'does-not-exist'");
-      }));
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken/package.json
deleted file mode 100644
index f830e8b60c02d..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken/package.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "name":
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken_code/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken_code/index.js
deleted file mode 100644
index bdb26504d6b6e..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken_code/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-const brokenRequire = require('does-not-exist'); // eslint-disable-line
-
-module.exports = function (kibana) {
-  return new kibana.Plugin({
-    id: 'foo',
-  });
-};
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken_code/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken_code/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/broken_code/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_number/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_number/index.js
deleted file mode 100644
index f24fc54e38d9a..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_number/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default 1;
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_number/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_number/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_number/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_object/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_object/index.js
deleted file mode 100644
index 59f4a2649f019..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_object/index.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default {
-  foo: 'bar',
-};
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_object/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_object/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_object/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_string/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_string/index.js
deleted file mode 100644
index 8900db15321ae..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_string/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default 'foo';
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_string/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_string/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/exports_string/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/foo/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/foo/index.js
deleted file mode 100644
index e43a1dcedb372..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/foo/index.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-module.exports = function (kibana) {
-  return new kibana.Plugin({
-    id: 'foo',
-  });
-};
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/foo/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/foo/package.json
deleted file mode 100644
index e43c2f0bc984c..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/foo/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/index.js
deleted file mode 100644
index edb1dd15673da..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-console.log('hello world');
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/lib/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/lib/index.js
deleted file mode 100644
index 050ffdfbde9ea..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/lib/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { myLib } from './my_lib';
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/lib/my_lib.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/lib/my_lib.js
deleted file mode 100644
index 94e511632d9a6..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/lib/my_lib.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export function myLib() {
-  console.log('lib');
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/prebuilt/index.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/prebuilt/index.js
deleted file mode 100644
index 89744b2dd3fd9..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/prebuilt/index.js
+++ /dev/null
@@ -1,14 +0,0 @@
-/* eslint-disable */
-'use strict';
-
-Object.defineProperty(exports, "__esModule", {
-  value: true
-});
-
-exports.default = function (_ref) {
-  var Plugin = _ref.Plugin;
-
-  return new Plugin({
-    id: 'foo'
-  });
-};
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/prebuilt/package.json b/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/prebuilt/package.json
deleted file mode 100644
index b1b74e0e76b12..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/fixtures/plugins/prebuilt/package.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "name": "prebuilt"
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/package_json_at_path.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/package_json_at_path.js
deleted file mode 100644
index fa1033180954e..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/package_json_at_path.js
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve } from 'path';
-import { toArray } from 'rxjs/operators';
-
-import expect from '@kbn/expect';
-
-import { createPackageJsonAtPath$ } from '../package_json_at_path';
-import { PLUGINS_DIR, assertInvalidPackError, assertInvalidDirectoryError } from './utils';
-
-describe('plugin discovery/plugin_pack', () => {
-  describe('createPackageJsonAtPath$()', () => {
-    it('returns an observable', () => {
-      expect(createPackageJsonAtPath$()).to.have.property('subscribe').a('function');
-    });
-    it('gets the default provider from prebuilt babel modules', async () => {
-      const results = await createPackageJsonAtPath$(resolve(PLUGINS_DIR, 'prebuilt'))
-        .pipe(toArray())
-        .toPromise();
-      expect(results).to.have.length(1);
-      expect(results[0]).to.only.have.keys(['packageJson']);
-      expect(results[0].packageJson).to.be.an(Object);
-      expect(results[0].packageJson.directoryPath).to.be(resolve(PLUGINS_DIR, 'prebuilt'));
-      expect(results[0].packageJson.contents).to.eql({ name: 'prebuilt' });
-    });
-    describe('errors emitted as { error } results', () => {
-      async function checkError(path, check) {
-        const results = await createPackageJsonAtPath$(path).pipe(toArray()).toPromise();
-        expect(results).to.have.length(1);
-        expect(results[0]).to.only.have.keys(['error']);
-        const { error } = results[0];
-        await check(error);
-      }
-      it('undefined path', () =>
-        checkError(undefined, (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('path must be a string');
-        }));
-      it('relative path', () =>
-        checkError('plugins/foo', (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('path must be absolute');
-        }));
-      it('./relative path', () =>
-        checkError('./plugins/foo', (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('path must be absolute');
-        }));
-      it('non-existent path', () =>
-        checkError(resolve(PLUGINS_DIR, 'baz'), (error) => {
-          assertInvalidPackError(error);
-          expect(error.message).to.contain('must be a directory');
-        }));
-      it('path to a file', () =>
-        checkError(resolve(PLUGINS_DIR, 'index.js'), (error) => {
-          assertInvalidPackError(error);
-          expect(error.message).to.contain('must be a directory');
-        }));
-      it('directory without a package.json', () =>
-        checkError(resolve(PLUGINS_DIR, 'lib'), (error) => {
-          assertInvalidPackError(error);
-          expect(error.message).to.contain('must have a package.json file');
-        }));
-      it('directory with an invalid package.json', () =>
-        checkError(resolve(PLUGINS_DIR, 'broken'), (error) => {
-          assertInvalidPackError(error);
-          expect(error.message).to.contain('must have a valid package.json file');
-        }));
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/package_jsons_in_directory.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/package_jsons_in_directory.js
deleted file mode 100644
index 37cb4cc064da7..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/package_jsons_in_directory.js
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve } from 'path';
-
-import { toArray } from 'rxjs/operators';
-import expect from '@kbn/expect';
-
-import { createPackageJsonsInDirectory$ } from '../package_jsons_in_directory';
-
-import { PLUGINS_DIR, assertInvalidDirectoryError } from './utils';
-
-describe('plugin discovery/packs in directory', () => {
-  describe('createPackageJsonsInDirectory$()', () => {
-    describe('errors emitted as { error } results', () => {
-      async function checkError(path, check) {
-        const results = await createPackageJsonsInDirectory$(path).pipe(toArray()).toPromise();
-        expect(results).to.have.length(1);
-        expect(results[0]).to.only.have.keys('error');
-        const { error } = results[0];
-        await check(error);
-      }
-
-      it('undefined path', () =>
-        checkError(undefined, (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('path must be a string');
-        }));
-      it('relative path', () =>
-        checkError('my/plugins', (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('path must be absolute');
-        }));
-      it('./relative path', () =>
-        checkError('./my/pluginsd', (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('path must be absolute');
-        }));
-      it('non-existent path', () =>
-        checkError(resolve(PLUGINS_DIR, 'notreal'), (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('no such file or directory');
-        }));
-      it('path to a file', () =>
-        checkError(resolve(PLUGINS_DIR, 'index.js'), (error) => {
-          assertInvalidDirectoryError(error);
-          expect(error.message).to.contain('not a directory');
-        }));
-    });
-
-    it('includes child errors for invalid packageJsons within a valid directory', async () => {
-      const results = await createPackageJsonsInDirectory$(PLUGINS_DIR).pipe(toArray()).toPromise();
-
-      const errors = results.map((result) => result.error).filter(Boolean);
-
-      const packageJsons = results.map((result) => result.packageJson).filter(Boolean);
-
-      packageJsons.forEach((pack) => expect(pack).to.be.an(Object));
-      // there should be one result for each item in PLUGINS_DIR
-      expect(results).to.have.length(8);
-      // three of the fixtures are errors of some sort
-      expect(errors).to.have.length(2);
-      // six of them are valid
-      expect(packageJsons).to.have.length(6);
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/plugin_pack.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/plugin_pack.js
deleted file mode 100644
index 769fcd74ce6fb..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/plugin_pack.js
+++ /dev/null
@@ -1,126 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import expect from '@kbn/expect';
-import sinon from 'sinon';
-
-import { PluginPack } from '../plugin_pack';
-import { PluginSpec } from '../../plugin_spec';
-
-describe('plugin discovery/plugin pack', () => {
-  describe('constructor', () => {
-    it('requires an object', () => {
-      expect(() => {
-        new PluginPack();
-      }).to.throwError();
-    });
-  });
-  describe('#getPkg()', () => {
-    it('returns the `pkg` constructor argument', () => {
-      const pkg = {};
-      const pack = new PluginPack({ pkg });
-      expect(pack.getPkg()).to.be(pkg);
-    });
-  });
-  describe('#getPath()', () => {
-    it('returns the `path` constructor argument', () => {
-      const path = {};
-      const pack = new PluginPack({ path });
-      expect(pack.getPath()).to.be(path);
-    });
-  });
-  describe('#getPluginSpecs()', () => {
-    it('calls the `provider` constructor argument with an api including a single sub class of PluginSpec', () => {
-      const provider = sinon.stub();
-      const pack = new PluginPack({ provider });
-      sinon.assert.notCalled(provider);
-      pack.getPluginSpecs();
-      sinon.assert.calledOnce(provider);
-      sinon.assert.calledWithExactly(provider, {
-        Plugin: sinon.match((Class) => {
-          return Class.prototype instanceof PluginSpec;
-        }, 'Subclass of PluginSpec'),
-      });
-    });
-
-    it('casts undefined return value to array', () => {
-      const pack = new PluginPack({ provider: () => undefined });
-      expect(pack.getPluginSpecs()).to.eql([]);
-    });
-
-    it('casts single PluginSpec to an array', () => {
-      const pack = new PluginPack({
-        path: '/dev/null',
-        pkg: { name: 'foo', version: 'kibana' },
-        provider: ({ Plugin }) => new Plugin({}),
-      });
-
-      const specs = pack.getPluginSpecs();
-      expect(specs).to.be.an('array');
-      expect(specs).to.have.length(1);
-      expect(specs[0]).to.be.a(PluginSpec);
-    });
-
-    it('returns an array of PluginSpec', () => {
-      const pack = new PluginPack({
-        path: '/dev/null',
-        pkg: { name: 'foo', version: 'kibana' },
-        provider: ({ Plugin }) => [new Plugin({}), new Plugin({})],
-      });
-
-      const specs = pack.getPluginSpecs();
-      expect(specs).to.be.an('array');
-      expect(specs).to.have.length(2);
-      expect(specs[0]).to.be.a(PluginSpec);
-      expect(specs[1]).to.be.a(PluginSpec);
-    });
-
-    it('throws if non-undefined return value is not an instance of api.Plugin', () => {
-      let OtherPluginSpecClass;
-      const otherPack = new PluginPack({
-        path: '/dev/null',
-        pkg: { name: 'foo', version: 'kibana' },
-        provider: (api) => {
-          OtherPluginSpecClass = api.Plugin;
-        },
-      });
-
-      // call getPluginSpecs() on other pack to get it's api.Plugin class
-      otherPack.getPluginSpecs();
-
-      const badPacks = [
-        new PluginPack({ provider: () => false }),
-        new PluginPack({ provider: () => null }),
-        new PluginPack({ provider: () => 1 }),
-        new PluginPack({ provider: () => 'true' }),
-        new PluginPack({ provider: () => true }),
-        new PluginPack({ provider: () => new Date() }),
-        new PluginPack({ provider: () => /foo.*bar/ }),
-        new PluginPack({ provider: () => function () {} }),
-        new PluginPack({ provider: () => new OtherPluginSpecClass({}) }),
-      ];
-
-      for (const pack of badPacks) {
-        expect(() => pack.getPluginSpecs()).to.throwError((error) => {
-          expect(error.message).to.contain('unexpected plugin export');
-        });
-      }
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_pack/__tests__/utils.js b/src/legacy/plugin_discovery/plugin_pack/__tests__/utils.js
deleted file mode 100644
index adcf60d809ff7..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/__tests__/utils.js
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve } from 'path';
-import { inspect } from 'util';
-
-import { isInvalidPackError, isInvalidDirectoryError } from '../../errors';
-
-export const PLUGINS_DIR = resolve(__dirname, 'fixtures/plugins');
-
-export function assertInvalidDirectoryError(error) {
-  if (!isInvalidDirectoryError(error)) {
-    throw new Error(`Expected ${inspect(error)} to be an 'InvalidDirectoryError'`);
-  }
-}
-
-export function assertInvalidPackError(error) {
-  if (!isInvalidPackError(error)) {
-    throw new Error(`Expected ${inspect(error)} to be an 'InvalidPackError'`);
-  }
-}
diff --git a/src/legacy/plugin_discovery/plugin_pack/create_pack.js b/src/legacy/plugin_discovery/plugin_pack/create_pack.js
deleted file mode 100644
index 189c2ea324103..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/create_pack.js
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { PluginPack } from './plugin_pack';
-import { map, catchError } from 'rxjs/operators';
-import { createInvalidPackError } from '../errors';
-
-function createPack(packageJson) {
-  let provider = require(packageJson.directoryPath); // eslint-disable-line import/no-dynamic-require
-  if (provider.__esModule) {
-    provider = provider.default;
-  }
-  if (typeof provider !== 'function') {
-    throw createInvalidPackError(packageJson.directoryPath, 'must export a function');
-  }
-
-  return new PluginPack({ path: packageJson.directoryPath, pkg: packageJson.contents, provider });
-}
-
-export const createPack$ = (packageJson$) =>
-  packageJson$.pipe(
-    map(({ error, packageJson }) => {
-      if (error) {
-        return { error };
-      }
-
-      if (!packageJson) {
-        throw new Error('packageJson is required to create the pack');
-      }
-
-      return {
-        pack: createPack(packageJson),
-      };
-    }),
-    // createPack can throw errors, and we want them to be represented
-    // like the errors we consume from createPackageJsonAtPath/Directory
-    catchError((error) => [{ error }])
-  );
diff --git a/src/legacy/plugin_discovery/plugin_pack/index.js b/src/legacy/plugin_discovery/plugin_pack/index.js
deleted file mode 100644
index 69e55baee660b..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/index.js
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { createPack$ } from './create_pack';
-export { createPackageJsonAtPath$ } from './package_json_at_path';
-export { createPackageJsonsInDirectory$ } from './package_jsons_in_directory';
-export { PluginPack } from './plugin_pack';
diff --git a/src/legacy/plugin_discovery/plugin_pack/lib/fs.js b/src/legacy/plugin_discovery/plugin_pack/lib/fs.js
deleted file mode 100644
index 2b531e314df52..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/lib/fs.js
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { stat, readdir } from 'fs';
-import { resolve, isAbsolute } from 'path';
-
-import { fromNode as fcb } from 'bluebird';
-import * as Rx from 'rxjs';
-import { catchError, mergeAll, filter, map, mergeMap } from 'rxjs/operators';
-
-import { createInvalidDirectoryError } from '../../errors';
-
-function assertAbsolutePath(path) {
-  if (typeof path !== 'string') {
-    throw createInvalidDirectoryError(new TypeError('path must be a string'), path);
-  }
-
-  if (!isAbsolute(path)) {
-    throw createInvalidDirectoryError(new TypeError('path must be absolute'), path);
-  }
-}
-
-async function statTest(path, test) {
-  try {
-    const stats = await fcb((cb) => stat(path, cb));
-    return Boolean(test(stats));
-  } catch (error) {
-    if (error.code !== 'ENOENT') {
-      throw error;
-    }
-  }
-  return false;
-}
-
-/**
- *  Determine if a path currently points to a directory
- *  @param  {String} path
- *  @return {Promise<boolean>}
- */
-export async function isDirectory(path) {
-  assertAbsolutePath(path);
-  return await statTest(path, (stat) => stat.isDirectory());
-}
-
-/**
- *  Get absolute paths for child directories within a path
- *  @param  {string} path
- *  @return {Promise<Array<string>>}
- */
-export const createChildDirectory$ = (path) =>
-  Rx.defer(() => {
-    assertAbsolutePath(path);
-    return fcb((cb) => readdir(path, cb));
-  }).pipe(
-    catchError((error) => {
-      throw createInvalidDirectoryError(error, path);
-    }),
-    mergeAll(),
-    filter((name) => !name.startsWith('.')),
-    map((name) => resolve(path, name)),
-    mergeMap(async (absolute) => {
-      if (await isDirectory(absolute)) {
-        return [absolute];
-      } else {
-        return [];
-      }
-    }),
-    mergeAll()
-  );
diff --git a/src/legacy/plugin_discovery/plugin_pack/lib/index.js b/src/legacy/plugin_discovery/plugin_pack/lib/index.js
deleted file mode 100644
index 491deeda27516..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/lib/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { isDirectory, createChildDirectory$ } from './fs';
diff --git a/src/legacy/plugin_discovery/plugin_pack/package_json_at_path.js b/src/legacy/plugin_discovery/plugin_pack/package_json_at_path.js
deleted file mode 100644
index 18629ef3ea802..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/package_json_at_path.js
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { readFileSync } from 'fs';
-import * as Rx from 'rxjs';
-import { map, mergeMap, catchError } from 'rxjs/operators';
-import { resolve } from 'path';
-import { createInvalidPackError } from '../errors';
-// eslint-disable-next-line @kbn/eslint/no-restricted-paths
-import { isNewPlatformPlugin } from '../../../core/server/plugins';
-
-import { isDirectory } from './lib';
-
-async function createPackageJsonAtPath(path) {
-  if (!(await isDirectory(path))) {
-    throw createInvalidPackError(path, 'must be a directory');
-  }
-
-  let str;
-  try {
-    str = readFileSync(resolve(path, 'package.json'));
-  } catch (err) {
-    throw createInvalidPackError(path, 'must have a package.json file');
-  }
-
-  let pkg;
-  try {
-    pkg = JSON.parse(str);
-  } catch (err) {
-    throw createInvalidPackError(path, 'must have a valid package.json file');
-  }
-
-  return {
-    directoryPath: path,
-    contents: pkg,
-  };
-}
-
-export const createPackageJsonAtPath$ = (path) =>
-  // If plugin directory contains manifest file, we should skip it since it
-  // should have been handled by the core plugin system already.
-  Rx.defer(() => isNewPlatformPlugin(path)).pipe(
-    mergeMap((isNewPlatformPlugin) => (isNewPlatformPlugin ? [] : createPackageJsonAtPath(path))),
-    map((packageJson) => ({ packageJson })),
-    catchError((error) => [{ error }])
-  );
diff --git a/src/legacy/plugin_discovery/plugin_pack/package_jsons_in_directory.js b/src/legacy/plugin_discovery/plugin_pack/package_jsons_in_directory.js
deleted file mode 100644
index 5f0977f4829b8..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/package_jsons_in_directory.js
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { mergeMap, catchError } from 'rxjs/operators';
-import { isInvalidDirectoryError } from '../errors';
-
-import { createChildDirectory$ } from './lib';
-import { createPackageJsonAtPath$ } from './package_json_at_path';
-
-/**
- *  Finds the plugins within a directory. Results are
- *  an array of objects with either `pack` or `error`
- *  keys.
- *
- *   - `{ error }` results are provided when the path is not
- *     a directory, or one of the child directories is not a
- *     valid plugin pack.
- *   - `{ pack }` results are for discovered plugins defs
- *
- *  @param  {String} path
- *  @return {Array<{pack}|{error}>}
- */
-export const createPackageJsonsInDirectory$ = (path) =>
-  createChildDirectory$(path).pipe(
-    mergeMap(createPackageJsonAtPath$),
-    catchError((error) => {
-      // this error is produced by createChildDirectory$() when the path
-      // is invalid, we return them as an error result similar to how
-      // createPackAtPath$ works when it finds invalid packs in a directory
-      if (isInvalidDirectoryError(error)) {
-        return [{ error }];
-      }
-
-      throw error;
-    })
-  );
diff --git a/src/legacy/plugin_discovery/plugin_pack/plugin_pack.js b/src/legacy/plugin_discovery/plugin_pack/plugin_pack.js
deleted file mode 100644
index 1baf3d104ca84..0000000000000
--- a/src/legacy/plugin_discovery/plugin_pack/plugin_pack.js
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { inspect } from 'util';
-
-import { PluginSpec } from '../plugin_spec';
-
-export class PluginPack {
-  constructor({ path, pkg, provider }) {
-    this._path = path;
-    this._pkg = pkg;
-    this._provider = provider;
-  }
-
-  /**
-   *  Get the contents of this plugin pack's package.json file
-   *  @return {Object}
-   */
-  getPkg() {
-    return this._pkg;
-  }
-
-  /**
-   *  Get the absolute path to this plugin pack on disk
-   *  @return {String}
-   */
-  getPath() {
-    return this._path;
-  }
-
-  /**
-   *  Invoke the plugin pack's provider to get the list
-   *  of specs defined in this plugin.
-   *  @return {Array<PluginSpec>}
-   */
-  getPluginSpecs() {
-    const pack = this;
-    const api = {
-      Plugin: class ScopedPluginSpec extends PluginSpec {
-        constructor(options) {
-          super(pack, options);
-        }
-      },
-    };
-
-    const result = this._provider(api);
-    const specs = [].concat(result === undefined ? [] : result);
-
-    // verify that all specs are instances of passed "Plugin" class
-    specs.forEach((spec) => {
-      if (!(spec instanceof api.Plugin)) {
-        throw new TypeError('unexpected plugin export ' + inspect(spec));
-      }
-    });
-
-    return specs;
-  }
-}
diff --git a/src/legacy/plugin_discovery/plugin_spec/__tests__/is_version_compatible.js b/src/legacy/plugin_discovery/plugin_spec/__tests__/is_version_compatible.js
deleted file mode 100644
index 897184496af37..0000000000000
--- a/src/legacy/plugin_discovery/plugin_spec/__tests__/is_version_compatible.js
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import expect from '@kbn/expect';
-
-import { isVersionCompatible } from '../is_version_compatible';
-
-describe('plugin discovery/plugin spec', () => {
-  describe('isVersionCompatible()', () => {
-    const tests = [
-      ['kibana', '6.0.0', true],
-      ['kibana', '6.0.0-rc1', true],
-      ['6.0.0-rc1', '6.0.0', true],
-      ['6.0.0', '6.0.0-rc1', true],
-      ['6.0.0-rc2', '6.0.0-rc1', true],
-      ['6.0.0-rc2', '6.0.0-rc3', true],
-      ['foo', 'bar', false],
-      ['6.0.0', '5.1.4', false],
-      ['5.1.4', '6.0.0', false],
-      ['5.1.4-SNAPSHOT', '6.0.0-rc2-SNAPSHOT', false],
-      ['5.1.4', '6.0.0-rc2-SNAPSHOT', false],
-      ['5.1.4-SNAPSHOT', '6.0.0', false],
-      ['5.1.4-SNAPSHOT', '6.0.0-rc2', false],
-    ];
-
-    for (const [plugin, kibana, shouldPass] of tests) {
-      it(`${shouldPass ? 'should' : `shouldn't`} allow plugin: ${plugin} kibana: ${kibana}`, () => {
-        expect(isVersionCompatible(plugin, kibana)).to.be(shouldPass);
-      });
-    }
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_spec/__tests__/plugin_spec.js b/src/legacy/plugin_discovery/plugin_spec/__tests__/plugin_spec.js
deleted file mode 100644
index 02675f0bd60f8..0000000000000
--- a/src/legacy/plugin_discovery/plugin_spec/__tests__/plugin_spec.js
+++ /dev/null
@@ -1,496 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve } from 'path';
-
-import expect from '@kbn/expect';
-import sinon from 'sinon';
-
-import { PluginPack } from '../../plugin_pack';
-import { PluginSpec } from '../plugin_spec';
-import * as IsVersionCompatibleNS from '../is_version_compatible';
-
-const fooPack = new PluginPack({
-  path: '/dev/null',
-  pkg: { name: 'foo', version: 'kibana' },
-});
-
-describe('plugin discovery/plugin spec', () => {
-  describe('PluginSpec', () => {
-    describe('validation', () => {
-      it('throws if missing spec.id AND Pack has no name', () => {
-        const pack = new PluginPack({ pkg: {} });
-        expect(() => new PluginSpec(pack, {})).to.throwError((error) => {
-          expect(error.message).to.contain('Unable to determine plugin id');
-        });
-      });
-
-      it('throws if missing spec.kibanaVersion AND Pack has no version', () => {
-        const pack = new PluginPack({ pkg: { name: 'foo' } });
-        expect(() => new PluginSpec(pack, {})).to.throwError((error) => {
-          expect(error.message).to.contain('Unable to determine plugin version');
-        });
-      });
-
-      it('throws if spec.require is defined, but not an array', () => {
-        function assert(require) {
-          expect(() => new PluginSpec(fooPack, { require })).to.throwError((error) => {
-            expect(error.message).to.contain('"plugin.require" must be an array of plugin ids');
-          });
-        }
-
-        assert(null);
-        assert('');
-        assert('kibana');
-        assert(1);
-        assert(0);
-        assert(/a.*b/);
-      });
-
-      it('throws if spec.publicDir is truthy and not a string', () => {
-        function assert(publicDir) {
-          expect(() => new PluginSpec(fooPack, { publicDir })).to.throwError((error) => {
-            expect(error.message).to.contain(
-              `The "path" argument must be of type string. Received type ${typeof publicDir}`
-            );
-          });
-        }
-
-        assert(1);
-        assert(function () {});
-        assert([]);
-        assert(/a.*b/);
-      });
-
-      it('throws if spec.publicDir is not an absolute path', () => {
-        function assert(publicDir) {
-          expect(() => new PluginSpec(fooPack, { publicDir })).to.throwError((error) => {
-            expect(error.message).to.contain('plugin.publicDir must be an absolute path');
-          });
-        }
-
-        assert('relative/path');
-        assert('./relative/path');
-      });
-
-      it('throws if spec.publicDir basename is not `public`', () => {
-        function assert(publicDir) {
-          expect(() => new PluginSpec(fooPack, { publicDir })).to.throwError((error) => {
-            expect(error.message).to.contain('must end with a "public" directory');
-          });
-        }
-
-        assert('/www');
-        assert('/www/');
-        assert('/www/public/my_plugin');
-        assert('/www/public/my_plugin/');
-      });
-    });
-
-    describe('#getPack()', () => {
-      it('returns the pack', () => {
-        const spec = new PluginSpec(fooPack, {});
-        expect(spec.getPack()).to.be(fooPack);
-      });
-    });
-
-    describe('#getPkg()', () => {
-      it('returns the pkg from the pack', () => {
-        const spec = new PluginSpec(fooPack, {});
-        expect(spec.getPkg()).to.be(fooPack.getPkg());
-      });
-    });
-
-    describe('#getPath()', () => {
-      it('returns the path from the pack', () => {
-        const spec = new PluginSpec(fooPack, {});
-        expect(spec.getPath()).to.be(fooPack.getPath());
-      });
-    });
-
-    describe('#getId()', () => {
-      it('uses spec.id', () => {
-        const spec = new PluginSpec(fooPack, {
-          id: 'bar',
-        });
-
-        expect(spec.getId()).to.be('bar');
-      });
-
-      it('defaults to pack.pkg.name', () => {
-        const spec = new PluginSpec(fooPack, {});
-
-        expect(spec.getId()).to.be('foo');
-      });
-    });
-
-    describe('#getVersion()', () => {
-      it('uses spec.version', () => {
-        const spec = new PluginSpec(fooPack, {
-          version: 'bar',
-        });
-
-        expect(spec.getVersion()).to.be('bar');
-      });
-
-      it('defaults to pack.pkg.version', () => {
-        const spec = new PluginSpec(fooPack, {});
-
-        expect(spec.getVersion()).to.be('kibana');
-      });
-    });
-
-    describe('#isEnabled()', () => {
-      describe('spec.isEnabled is not defined', () => {
-        function setup(configPrefix, configGetImpl) {
-          const spec = new PluginSpec(fooPack, { configPrefix });
-          const config = {
-            get: sinon.spy(configGetImpl),
-            has: sinon.stub(),
-          };
-
-          return { spec, config };
-        }
-
-        it('throws if not passed a config service', () => {
-          const { spec } = setup('a.b.c', () => true);
-
-          expect(() => spec.isEnabled()).to.throwError((error) => {
-            expect(error.message).to.contain('must be called with a config service');
-          });
-          expect(() => spec.isEnabled(null)).to.throwError((error) => {
-            expect(error.message).to.contain('must be called with a config service');
-          });
-          expect(() => spec.isEnabled({ get: () => {} })).to.throwError((error) => {
-            expect(error.message).to.contain('must be called with a config service');
-          });
-        });
-
-        it('returns true when config.get([...configPrefix, "enabled"]) returns true', () => {
-          const { spec, config } = setup('d.e.f', () => true);
-
-          expect(spec.isEnabled(config)).to.be(true);
-          sinon.assert.calledOnce(config.get);
-          sinon.assert.calledWithExactly(config.get, ['d', 'e', 'f', 'enabled']);
-        });
-
-        it('returns false when config.get([...configPrefix, "enabled"]) returns false', () => {
-          const { spec, config } = setup('g.h.i', () => false);
-
-          expect(spec.isEnabled(config)).to.be(false);
-          sinon.assert.calledOnce(config.get);
-          sinon.assert.calledWithExactly(config.get, ['g', 'h', 'i', 'enabled']);
-        });
-      });
-
-      describe('spec.isEnabled is defined', () => {
-        function setup(isEnabledImpl) {
-          const isEnabled = sinon.spy(isEnabledImpl);
-          const spec = new PluginSpec(fooPack, { isEnabled });
-          const config = {
-            get: sinon.stub(),
-            has: sinon.stub(),
-          };
-
-          return { isEnabled, spec, config };
-        }
-
-        it('throws if not passed a config service', () => {
-          const { spec } = setup(() => true);
-
-          expect(() => spec.isEnabled()).to.throwError((error) => {
-            expect(error.message).to.contain('must be called with a config service');
-          });
-          expect(() => spec.isEnabled(null)).to.throwError((error) => {
-            expect(error.message).to.contain('must be called with a config service');
-          });
-          expect(() => spec.isEnabled({ get: () => {} })).to.throwError((error) => {
-            expect(error.message).to.contain('must be called with a config service');
-          });
-        });
-
-        it('does not check config if spec.isEnabled returns true', () => {
-          const { spec, isEnabled, config } = setup(() => true);
-
-          expect(spec.isEnabled(config)).to.be(true);
-          sinon.assert.calledOnce(isEnabled);
-          sinon.assert.notCalled(config.get);
-        });
-
-        it('does not check config if spec.isEnabled returns false', () => {
-          const { spec, isEnabled, config } = setup(() => false);
-
-          expect(spec.isEnabled(config)).to.be(false);
-          sinon.assert.calledOnce(isEnabled);
-          sinon.assert.notCalled(config.get);
-        });
-      });
-    });
-
-    describe('#getExpectedKibanaVersion()', () => {
-      describe('has: spec.kibanaVersion,pkg.kibana.version,spec.version,pkg.version', () => {
-        it('uses spec.kibanaVersion', () => {
-          const pack = new PluginPack({
-            path: '/dev/null',
-            pkg: {
-              name: 'expkv',
-              version: '1.0.0',
-              kibana: {
-                version: '6.0.0',
-              },
-            },
-          });
-
-          const spec = new PluginSpec(pack, {
-            version: '2.0.0',
-            kibanaVersion: '5.0.0',
-          });
-
-          expect(spec.getExpectedKibanaVersion()).to.be('5.0.0');
-        });
-      });
-      describe('missing: spec.kibanaVersion, has: pkg.kibana.version,spec.version,pkg.version', () => {
-        it('uses pkg.kibana.version', () => {
-          const pack = new PluginPack({
-            path: '/dev/null',
-            pkg: {
-              name: 'expkv',
-              version: '1.0.0',
-              kibana: {
-                version: '6.0.0',
-              },
-            },
-          });
-
-          const spec = new PluginSpec(pack, {
-            version: '2.0.0',
-          });
-
-          expect(spec.getExpectedKibanaVersion()).to.be('6.0.0');
-        });
-      });
-      describe('missing: spec.kibanaVersion,pkg.kibana.version, has: spec.version,pkg.version', () => {
-        it('uses spec.version', () => {
-          const pack = new PluginPack({
-            path: '/dev/null',
-            pkg: {
-              name: 'expkv',
-              version: '1.0.0',
-            },
-          });
-
-          const spec = new PluginSpec(pack, {
-            version: '2.0.0',
-          });
-
-          expect(spec.getExpectedKibanaVersion()).to.be('2.0.0');
-        });
-      });
-      describe('missing: spec.kibanaVersion,pkg.kibana.version,spec.version, has: pkg.version', () => {
-        it('uses pkg.version', () => {
-          const pack = new PluginPack({
-            path: '/dev/null',
-            pkg: {
-              name: 'expkv',
-              version: '1.0.0',
-            },
-          });
-
-          const spec = new PluginSpec(pack, {});
-
-          expect(spec.getExpectedKibanaVersion()).to.be('1.0.0');
-        });
-      });
-    });
-
-    describe('#isVersionCompatible()', () => {
-      it('passes this.getExpectedKibanaVersion() and arg to isVersionCompatible(), returns its result', () => {
-        const spec = new PluginSpec(fooPack, { version: '1.0.0' });
-        sinon.stub(spec, 'getExpectedKibanaVersion').returns('foo');
-        const isVersionCompatible = sinon
-          .stub(IsVersionCompatibleNS, 'isVersionCompatible')
-          .returns('bar');
-        expect(spec.isVersionCompatible('baz')).to.be('bar');
-
-        sinon.assert.calledOnce(spec.getExpectedKibanaVersion);
-        sinon.assert.calledWithExactly(spec.getExpectedKibanaVersion);
-
-        sinon.assert.calledOnce(isVersionCompatible);
-        sinon.assert.calledWithExactly(isVersionCompatible, 'foo', 'baz');
-      });
-    });
-
-    describe('#getRequiredPluginIds()', () => {
-      it('returns spec.require', () => {
-        const spec = new PluginSpec(fooPack, { require: [1, 2, 3] });
-        expect(spec.getRequiredPluginIds()).to.eql([1, 2, 3]);
-      });
-    });
-
-    describe('#getPublicDir()', () => {
-      describe('spec.publicDir === false', () => {
-        it('returns null', () => {
-          const spec = new PluginSpec(fooPack, { publicDir: false });
-          expect(spec.getPublicDir()).to.be(null);
-        });
-      });
-
-      describe('spec.publicDir is falsy', () => {
-        it('returns public child of pack path', () => {
-          function assert(publicDir) {
-            const spec = new PluginSpec(fooPack, { publicDir });
-            expect(spec.getPublicDir()).to.be(resolve('/dev/null/public'));
-          }
-
-          assert(0);
-          assert('');
-          assert(null);
-          assert(undefined);
-          assert(NaN);
-        });
-      });
-
-      describe('spec.publicDir is an absolute path', () => {
-        it('returns the path', () => {
-          const spec = new PluginSpec(fooPack, {
-            publicDir: '/var/www/public',
-          });
-
-          expect(spec.getPublicDir()).to.be('/var/www/public');
-        });
-      });
-
-      // NOTE: see constructor tests for other truthy-tests that throw in constructor
-    });
-
-    describe('#getExportSpecs()', () => {
-      it('returns spec.uiExports', () => {
-        const spec = new PluginSpec(fooPack, {
-          uiExports: 'foo',
-        });
-
-        expect(spec.getExportSpecs()).to.be('foo');
-      });
-    });
-
-    describe('#getPreInitHandler()', () => {
-      it('returns spec.preInit', () => {
-        const spec = new PluginSpec(fooPack, {
-          preInit: 'foo',
-        });
-
-        expect(spec.getPreInitHandler()).to.be('foo');
-      });
-    });
-
-    describe('#getInitHandler()', () => {
-      it('returns spec.init', () => {
-        const spec = new PluginSpec(fooPack, {
-          init: 'foo',
-        });
-
-        expect(spec.getInitHandler()).to.be('foo');
-      });
-    });
-
-    describe('#getConfigPrefix()', () => {
-      describe('spec.configPrefix is truthy', () => {
-        it('returns spec.configPrefix', () => {
-          const spec = new PluginSpec(fooPack, {
-            configPrefix: 'foo.bar.baz',
-          });
-
-          expect(spec.getConfigPrefix()).to.be('foo.bar.baz');
-        });
-      });
-      describe('spec.configPrefix is falsy', () => {
-        it('returns spec.getId()', () => {
-          function assert(configPrefix) {
-            const spec = new PluginSpec(fooPack, { configPrefix });
-            sinon.stub(spec, 'getId').returns('foo');
-            expect(spec.getConfigPrefix()).to.be('foo');
-            sinon.assert.calledOnce(spec.getId);
-          }
-
-          assert(false);
-          assert(null);
-          assert(undefined);
-          assert('');
-          assert(0);
-        });
-      });
-    });
-
-    describe('#getConfigSchemaProvider()', () => {
-      it('returns spec.config', () => {
-        const spec = new PluginSpec(fooPack, {
-          config: 'foo',
-        });
-
-        expect(spec.getConfigSchemaProvider()).to.be('foo');
-      });
-    });
-
-    describe('#readConfigValue()', () => {
-      const spec = new PluginSpec(fooPack, {
-        configPrefix: 'foo.bar',
-      });
-
-      const config = {
-        get: sinon.stub(),
-      };
-
-      afterEach(() => config.get.resetHistory());
-
-      describe('key = "foo"', () => {
-        it('passes key as own array item', () => {
-          spec.readConfigValue(config, 'foo');
-          sinon.assert.calledOnce(config.get);
-          sinon.assert.calledWithExactly(config.get, ['foo', 'bar', 'foo']);
-        });
-      });
-
-      describe('key = "foo.bar"', () => {
-        it('passes key as two array items', () => {
-          spec.readConfigValue(config, 'foo.bar');
-          sinon.assert.calledOnce(config.get);
-          sinon.assert.calledWithExactly(config.get, ['foo', 'bar', 'foo', 'bar']);
-        });
-      });
-
-      describe('key = ["foo", "bar"]', () => {
-        it('merged keys into array', () => {
-          spec.readConfigValue(config, ['foo', 'bar']);
-          sinon.assert.calledOnce(config.get);
-          sinon.assert.calledWithExactly(config.get, ['foo', 'bar', 'foo', 'bar']);
-        });
-      });
-    });
-
-    describe('#getDeprecationsProvider()', () => {
-      it('returns spec.deprecations', () => {
-        const spec = new PluginSpec(fooPack, {
-          deprecations: 'foo',
-        });
-
-        expect(spec.getDeprecationsProvider()).to.be('foo');
-      });
-    });
-  });
-});
diff --git a/src/legacy/plugin_discovery/plugin_spec/index.js b/src/legacy/plugin_discovery/plugin_spec/index.js
deleted file mode 100644
index 671d311b152e2..0000000000000
--- a/src/legacy/plugin_discovery/plugin_spec/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { PluginSpec } from './plugin_spec';
diff --git a/src/legacy/plugin_discovery/plugin_spec/is_version_compatible.js b/src/legacy/plugin_discovery/plugin_spec/is_version_compatible.js
deleted file mode 100644
index 6822c168f368d..0000000000000
--- a/src/legacy/plugin_discovery/plugin_spec/is_version_compatible.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { cleanVersion, versionSatisfies } from '../../utils/version';
-
-export function isVersionCompatible(version, compatibleWith) {
-  // the special "kibana" version can be used to always be compatible,
-  // but is intentionally not supported by the plugin installer
-  if (version === 'kibana') {
-    return true;
-  }
-
-  return versionSatisfies(cleanVersion(version), cleanVersion(compatibleWith));
-}
diff --git a/src/legacy/plugin_discovery/plugin_spec/plugin_spec.js b/src/legacy/plugin_discovery/plugin_spec/plugin_spec.js
deleted file mode 100644
index db1ec425f2ce5..0000000000000
--- a/src/legacy/plugin_discovery/plugin_spec/plugin_spec.js
+++ /dev/null
@@ -1,210 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { resolve, basename, isAbsolute as isAbsolutePath } from 'path';
-
-import { get, toPath } from 'lodash';
-
-import { createInvalidPluginError } from '../errors';
-import { isVersionCompatible } from './is_version_compatible';
-
-export class PluginSpec {
-  /**
-   * @param {PluginPack} pack The plugin pack that produced this spec
-   * @param {Object} opts the options for this plugin
-   * @param {String} [opts.id=pkg.name] the id for this plugin.
-   * @param {Object} [opts.uiExports] a mapping of UiExport types to
-   * UI modules or metadata about the UI module
-   * @param {Array} [opts.require] the other plugins that this plugin
-   * requires. These plugins must exist and be enabled for this plugin
-   * to function. The require'd plugins will also be initialized first,
-   * in order to make sure that dependencies provided by these plugins
-   * are available
-   * @param {String} [opts.version=pkg.version] the version of this plugin
-   * @param {Function} [opts.init] A function that will be called to initialize
-   * this plugin at the appropriate time.
-   * @param {Function} [opts.configPrefix=this.id] The prefix to use for
-   * configuration values in the main configuration service
-   * @param {Function} [opts.config] A function that produces a configuration
-   * schema using Joi, which is passed as its first argument.
-   * @param {String|False} [opts.publicDir=path + '/public'] the public
-   * directory for this plugin. The final directory must have the name "public",
-   * though it can be located somewhere besides the root of the plugin. Set
-   * this to false to disable exposure of a public directory
-   */
-  constructor(pack, options) {
-    const {
-      id,
-      require,
-      version,
-      kibanaVersion,
-      uiExports,
-      uiCapabilities,
-      publicDir,
-      configPrefix,
-      config,
-      deprecations,
-      preInit,
-      init,
-      postInit,
-      isEnabled,
-    } = options;
-
-    this._id = id;
-    this._pack = pack;
-    this._version = version;
-    this._kibanaVersion = kibanaVersion;
-    this._require = require;
-
-    this._publicDir = publicDir;
-    this._uiExports = uiExports;
-    this._uiCapabilities = uiCapabilities;
-
-    this._configPrefix = configPrefix;
-    this._configSchemaProvider = config;
-    this._configDeprecationsProvider = deprecations;
-
-    this._isEnabled = isEnabled;
-    this._preInit = preInit;
-    this._init = init;
-    this._postInit = postInit;
-
-    if (!this.getId()) {
-      throw createInvalidPluginError(this, 'Unable to determine plugin id');
-    }
-
-    if (!this.getVersion()) {
-      throw createInvalidPluginError(this, 'Unable to determine plugin version');
-    }
-
-    if (this.getRequiredPluginIds() !== undefined && !Array.isArray(this.getRequiredPluginIds())) {
-      throw createInvalidPluginError(this, '"plugin.require" must be an array of plugin ids');
-    }
-
-    if (this._publicDir) {
-      if (!isAbsolutePath(this._publicDir)) {
-        throw createInvalidPluginError(this, 'plugin.publicDir must be an absolute path');
-      }
-      if (basename(this._publicDir) !== 'public') {
-        throw createInvalidPluginError(
-          this,
-          `publicDir for plugin ${this.getId()} must end with a "public" directory.`
-        );
-      }
-    }
-  }
-
-  getPack() {
-    return this._pack;
-  }
-
-  getPkg() {
-    return this._pack.getPkg();
-  }
-
-  getPath() {
-    return this._pack.getPath();
-  }
-
-  getId() {
-    return this._id || this.getPkg().name;
-  }
-
-  getVersion() {
-    return this._version || this.getPkg().version;
-  }
-
-  isEnabled(config) {
-    if (!config || typeof config.get !== 'function' || typeof config.has !== 'function') {
-      throw new TypeError('PluginSpec#isEnabled() must be called with a config service');
-    }
-
-    if (this._isEnabled) {
-      return this._isEnabled(config);
-    }
-
-    return Boolean(this.readConfigValue(config, 'enabled'));
-  }
-
-  getExpectedKibanaVersion() {
-    // Plugins must specify their version, and by default that version should match
-    // the version of kibana down to the patch level. If these two versions need
-    // to diverge, they can specify a kibana.version in the package to indicate the
-    // version of kibana the plugin is intended to work with.
-    return (
-      this._kibanaVersion || get(this.getPack().getPkg(), 'kibana.version') || this.getVersion()
-    );
-  }
-
-  isVersionCompatible(actualKibanaVersion) {
-    return isVersionCompatible(this.getExpectedKibanaVersion(), actualKibanaVersion);
-  }
-
-  getRequiredPluginIds() {
-    return this._require;
-  }
-
-  getPublicDir() {
-    if (this._publicDir === false) {
-      return null;
-    }
-
-    if (!this._publicDir) {
-      return resolve(this.getPack().getPath(), 'public');
-    }
-
-    return this._publicDir;
-  }
-
-  getExportSpecs() {
-    return this._uiExports;
-  }
-
-  getUiCapabilitiesProvider() {
-    return this._uiCapabilities;
-  }
-
-  getPreInitHandler() {
-    return this._preInit;
-  }
-
-  getInitHandler() {
-    return this._init;
-  }
-
-  getPostInitHandler() {
-    return this._postInit;
-  }
-
-  getConfigPrefix() {
-    return this._configPrefix || this.getId();
-  }
-
-  getConfigSchemaProvider() {
-    return this._configSchemaProvider;
-  }
-
-  readConfigValue(config, key) {
-    return config.get([...toPath(this.getConfigPrefix()), ...toPath(key)]);
-  }
-
-  getDeprecationsProvider() {
-    return this._configDeprecationsProvider;
-  }
-}
diff --git a/src/legacy/plugin_discovery/plugin_spec/plugin_spec_options.d.ts b/src/legacy/plugin_discovery/plugin_spec/plugin_spec_options.d.ts
deleted file mode 100644
index e1ed2f57375a4..0000000000000
--- a/src/legacy/plugin_discovery/plugin_spec/plugin_spec_options.d.ts
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-import { Server } from '../../server/kbn_server';
-import { Capabilities } from '../../../core/server';
-
-export type InitPluginFunction = (server: Server) => void;
-export interface UiExports {
-  injectDefaultVars?: (server: Server) => { [key: string]: any };
-}
-
-export interface PluginSpecOptions {
-  id: string;
-  require?: string[];
-  publicDir?: string;
-  uiExports?: UiExports;
-  uiCapabilities?: Capabilities;
-  init?: InitPluginFunction;
-  config?: any;
-}
diff --git a/src/legacy/plugin_discovery/types.ts b/src/legacy/plugin_discovery/types.ts
deleted file mode 100644
index 700ca6fa68c95..0000000000000
--- a/src/legacy/plugin_discovery/types.ts
+++ /dev/null
@@ -1,107 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { Server } from '../server/kbn_server';
-import { Capabilities } from '../../core/server';
-import { AppCategory } from '../../core/types';
-
-/**
- * Usage
- *
- * ```
- * const apmOss: LegacyPlugin = (kibana) => {
- *   return new kibana.Plugin({
- *     id: 'apm_oss',
- *     // ...
- *   });
- * };
- * ```
- */
-export type LegacyPluginInitializer = (kibana: LegacyPluginApi) => ArrayOrItem<LegacyPluginSpec>;
-
-export type ArrayOrItem<T> = T | T[];
-
-export interface LegacyPluginApi {
-  Plugin: new (options: Partial<LegacyPluginOptions>) => LegacyPluginSpec;
-}
-
-export interface LegacyPluginOptions {
-  id: string;
-  require: string[];
-  version: string;
-  kibanaVersion: 'kibana';
-  uiExports: Partial<{
-    app: Partial<{
-      title: string;
-      category?: AppCategory;
-      description: string;
-      main: string;
-      icon: string;
-      euiIconType: string;
-      order: number;
-      listed: boolean;
-    }>;
-    apps: any;
-    hacks: string[];
-    visualize: string[];
-    devTools: string[];
-    injectDefaultVars: (server: Server) => Record<string, any>;
-    home: string[];
-    mappings: any;
-    migrations: any;
-    visTypes: string[];
-    embeddableActions?: string[];
-    embeddableFactories?: string[];
-    uiSettingDefaults?: Record<string, any>;
-    interpreter: string | string[];
-  }>;
-  uiCapabilities?: Capabilities;
-  publicDir: any;
-  configPrefix: any;
-  config: any;
-  deprecations: any;
-  preInit: any;
-  init: InitPluginFunction;
-  postInit: any;
-  isEnabled: boolean;
-}
-
-export type InitPluginFunction = (server: Server) => void;
-
-export interface LegacyPluginSpec {
-  getPack(): any;
-  getPkg(): any;
-  getPath(): string;
-  getId(): string;
-  getVersion(): string;
-  isEnabled(config: any): boolean;
-  getExpectedKibanaVersion(): string;
-  isVersionCompatible(actualKibanaVersion: any): boolean;
-  getRequiredPluginIds(): string[];
-  getPublicDir(): string | null;
-  getExportSpecs(): any;
-  getUiCapabilitiesProvider(): any;
-  getPreInitHandler(): any;
-  getInitHandler(): any;
-  getPostInitHandler(): any;
-  getConfigPrefix(): string;
-  getConfigSchemaProvider(): any;
-  readConfigValue(config: any, key: string): any;
-  getDeprecationsProvider(): any;
-}
diff --git a/src/legacy/server/config/schema.js b/src/legacy/server/config/schema.js
index 3184dd421e7f2..648b21da54a44 100644
--- a/src/legacy/server/config/schema.js
+++ b/src/legacy/server/config/schema.js
@@ -132,6 +132,7 @@ export default () =>
       }),
     }).default(),
 
+    // still used by the legacy i18n mixin
     plugins: Joi.object({
       paths: Joi.array().items(Joi.string()).default([]),
       scanDirs: Joi.array().items(Joi.string()).default([]),
@@ -147,71 +148,8 @@ export default () =>
     status: Joi.object({
       allowAnonymous: Joi.boolean().default(false),
     }).default(),
-    map: Joi.object({
-      includeElasticMapsService: Joi.boolean().default(true),
-      proxyElasticMapsServiceInMaps: Joi.boolean().default(false),
-      tilemap: Joi.object({
-        url: Joi.string(),
-        options: Joi.object({
-          attribution: Joi.string(),
-          minZoom: Joi.number().min(0, 'Must be 0 or higher').default(0),
-          maxZoom: Joi.number().default(10),
-          tileSize: Joi.number(),
-          subdomains: Joi.array().items(Joi.string()).single(),
-          errorTileUrl: Joi.string().uri(),
-          tms: Joi.boolean(),
-          reuseTiles: Joi.boolean(),
-          bounds: Joi.array().items(Joi.array().items(Joi.number()).min(2).required()).min(2),
-          default: Joi.boolean(),
-        }).default({
-          default: true,
-        }),
-      }).default(),
-      regionmap: Joi.object({
-        includeElasticMapsService: Joi.boolean().default(true),
-        layers: Joi.array()
-          .items(
-            Joi.object({
-              url: Joi.string(),
-              format: Joi.object({
-                type: Joi.string().default('geojson'),
-              }).default({
-                type: 'geojson',
-              }),
-              meta: Joi.object({
-                feature_collection_path: Joi.string().default('data'),
-              }).default({
-                feature_collection_path: 'data',
-              }),
-              attribution: Joi.string(),
-              name: Joi.string(),
-              fields: Joi.array().items(
-                Joi.object({
-                  name: Joi.string(),
-                  description: Joi.string(),
-                })
-              ),
-            })
-          )
-          .default([]),
-      }).default(),
-      manifestServiceUrl: Joi.string().default('').allow(''),
-      emsFileApiUrl: Joi.string().default('https://vector.maps.elastic.co'),
-      emsTileApiUrl: Joi.string().default('https://tiles.maps.elastic.co'),
-      emsLandingPageUrl: Joi.string().default('https://maps.elastic.co/v7.9'),
-      emsFontLibraryUrl: Joi.string().default(
-        'https://tiles.maps.elastic.co/fonts/{fontstack}/{range}.pbf'
-      ),
-      emsTileLayerId: Joi.object({
-        bright: Joi.string().default('road_map'),
-        desaturated: Joi.string().default('road_map_desaturated'),
-        dark: Joi.string().default('dark_map'),
-      }).default({
-        bright: 'road_map',
-        desaturated: 'road_map_desaturated',
-        dark: 'dark_map',
-      }),
-    }).default(),
+
+    map: HANDLED_IN_NEW_PLATFORM,
 
     i18n: Joi.object({
       locale: Joi.string().default('en'),
diff --git a/src/legacy/server/kbn_server.d.ts b/src/legacy/server/kbn_server.d.ts
index 3cfda0e0696bb..1718a9a8f55da 100644
--- a/src/legacy/server/kbn_server.d.ts
+++ b/src/legacy/server/kbn_server.d.ts
@@ -26,11 +26,10 @@ import {
   LoggerFactory,
   PackageInfo,
   LegacyServiceSetupDeps,
-  LegacyServiceDiscoverPlugins,
 } from '../../core/server';
 
 // eslint-disable-next-line @kbn/eslint/no-restricted-paths
-import { LegacyConfig, ILegacyInternals } from '../../core/server/legacy';
+import { LegacyConfig } from '../../core/server/legacy';
 // eslint-disable-next-line @kbn/eslint/no-restricted-paths
 import { UiPlugins } from '../../core/server/plugins';
 
@@ -58,9 +57,7 @@ export interface PluginsSetup {
 
 export interface KibanaCore {
   __internals: {
-    elasticsearch: LegacyServiceSetupDeps['core']['elasticsearch'];
     hapiServer: LegacyServiceSetupDeps['core']['http']['server'];
-    legacy: ILegacyInternals;
     rendering: LegacyServiceSetupDeps['core']['rendering'];
     uiPlugins: UiPlugins;
   };
@@ -90,31 +87,18 @@ export interface NewPlatform {
   stop: null;
 }
 
-export type LegacyPlugins = Pick<
-  LegacyServiceDiscoverPlugins,
-  'pluginSpecs' | 'disabledPluginSpecs' | 'uiExports'
->;
-
 // eslint-disable-next-line import/no-default-export
 export default class KbnServer {
   public readonly newPlatform: NewPlatform;
   public server: Server;
   public inject: Server['inject'];
-  public pluginSpecs: any[];
-  public uiBundles: any;
 
-  constructor(
-    settings: Record<string, any>,
-    config: KibanaConfig,
-    core: KibanaCore,
-    legacyPlugins: LegacyPlugins
-  );
+  constructor(settings: Record<string, any>, config: KibanaConfig, core: KibanaCore);
 
   public ready(): Promise<void>;
   public mixin(...fns: KbnMixinFunc[]): Promise<void>;
   public listen(): Promise<Server>;
   public close(): Promise<void>;
-  public afterPluginsInit(callback: () => void): void;
   public applyLoggingConfiguration(settings: any): void;
   public config: KibanaConfig;
 }
diff --git a/src/legacy/server/kbn_server.js b/src/legacy/server/kbn_server.js
index 107e5f6387833..e29563a7c6266 100644
--- a/src/legacy/server/kbn_server.js
+++ b/src/legacy/server/kbn_server.js
@@ -30,7 +30,6 @@ import { loggingMixin } from './logging';
 import warningsMixin from './warnings';
 import configCompleteMixin from './config/complete';
 import { optimizeMixin } from '../../optimize';
-import * as Plugins from './plugins';
 import { uiMixin } from '../ui';
 import { i18nMixin } from './i18n';
 
@@ -47,9 +46,8 @@ export default class KbnServer {
    * @param {Record<string, any>} settings
    * @param {KibanaConfig} config
    * @param {KibanaCore} core
-   * @param {LegacyPlugins} legacyPlugins
    */
-  constructor(settings, config, core, legacyPlugins) {
+  constructor(settings, config, core) {
     this.name = pkg.name;
     this.version = pkg.version;
     this.build = pkg.build || false;
@@ -74,14 +72,8 @@ export default class KbnServer {
       stop: null,
     };
 
-    this.uiExports = legacyPlugins.uiExports;
-    this.pluginSpecs = legacyPlugins.pluginSpecs;
-    this.disabledPluginSpecs = legacyPlugins.disabledPluginSpecs;
-
     this.ready = constant(
       this.mixin(
-        Plugins.waitForInitSetupMixin,
-
         // Sets global HTTP behaviors
         httpMixin,
 
@@ -93,22 +85,13 @@ export default class KbnServer {
         // scan translations dirs, register locale files and initialize i18n engine.
         i18nMixin,
 
-        // find plugins and set this.plugins and this.pluginSpecs
-        Plugins.scanMixin,
-
         // tell the config we are done loading plugins
         configCompleteMixin,
 
         uiMixin,
 
         // setup routes that serve the @kbn/optimizer output
-        optimizeMixin,
-
-        // initialize the plugins
-        Plugins.initializeMixin,
-
-        // notify any deferred setup logic that plugins have initialized
-        Plugins.waitForInitResolveMixin
+        optimizeMixin
       )
     );
 
diff --git a/src/legacy/server/plugins/index.js b/src/legacy/server/plugins/index.js
deleted file mode 100644
index 1511b63b519ae..0000000000000
--- a/src/legacy/server/plugins/index.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { scanMixin } from './scan_mixin';
-export { initializeMixin } from './initialize_mixin';
-export { waitForInitSetupMixin, waitForInitResolveMixin } from './wait_for_plugins_init';
diff --git a/src/legacy/server/plugins/initialize_mixin.js b/src/legacy/server/plugins/initialize_mixin.js
deleted file mode 100644
index ccf4cd1c1a404..0000000000000
--- a/src/legacy/server/plugins/initialize_mixin.js
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { callPluginHook } from './lib';
-
-/**
- *  KbnServer mixin that initializes all plugins found in ./scan mixin
- *  @param  {KbnServer} kbnServer
- *  @param  {Hapi.Server} server
- *  @param  {Config} config
- *  @return {Promise<undefined>}
- */
-export async function initializeMixin(kbnServer, server, config) {
-  if (!config.get('plugins.initialize')) {
-    server.log(['info'], 'Plugin initialization disabled.');
-    return;
-  }
-
-  async function callHookOnPlugins(hookName) {
-    const { plugins } = kbnServer;
-    const ids = plugins.map((p) => p.id);
-
-    for (const id of ids) {
-      await callPluginHook(hookName, plugins, id, []);
-    }
-  }
-
-  await callHookOnPlugins('preInit');
-  await callHookOnPlugins('init');
-  await callHookOnPlugins('postInit');
-}
diff --git a/src/legacy/server/plugins/lib/call_plugin_hook.js b/src/legacy/server/plugins/lib/call_plugin_hook.js
deleted file mode 100644
index b665869f5d25f..0000000000000
--- a/src/legacy/server/plugins/lib/call_plugin_hook.js
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { last } from 'lodash';
-
-export async function callPluginHook(hookName, plugins, id, history) {
-  const plugin = plugins.find((plugin) => plugin.id === id);
-
-  // make sure this is a valid plugin id
-  if (!plugin) {
-    if (history.length) {
-      throw new Error(`Unmet requirement "${id}" for plugin "${last(history)}"`);
-    } else {
-      throw new Error(`Unknown plugin "${id}"`);
-    }
-  }
-
-  const circleStart = history.indexOf(id);
-  const path = [...history, id];
-
-  // make sure we are not trying to load a dependency within itself
-  if (circleStart > -1) {
-    const circle = path.slice(circleStart);
-    throw new Error(`circular dependency found: "${circle.join(' -> ')}"`);
-  }
-
-  // call hook on all dependencies
-  for (const req of plugin.requiredIds) {
-    await callPluginHook(hookName, plugins, req, path);
-  }
-
-  // call hook on this plugin
-  await plugin[hookName]();
-}
diff --git a/src/legacy/server/plugins/lib/call_plugin_hook.test.js b/src/legacy/server/plugins/lib/call_plugin_hook.test.js
deleted file mode 100644
index 30dc2d91a9ab2..0000000000000
--- a/src/legacy/server/plugins/lib/call_plugin_hook.test.js
+++ /dev/null
@@ -1,101 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import sinon from 'sinon';
-import { callPluginHook } from './call_plugin_hook';
-
-describe('server/plugins/callPluginHook', () => {
-  it('should call in correct order based on requirements', async () => {
-    const plugins = [
-      {
-        id: 'foo',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: ['bar', 'baz'],
-      },
-      {
-        id: 'bar',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: [],
-      },
-      {
-        id: 'baz',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: ['bar'],
-      },
-    ];
-
-    await callPluginHook('init', plugins, 'foo', []);
-    const [foo, bar, baz] = plugins;
-    sinon.assert.calledOnce(foo.init);
-    sinon.assert.calledTwice(bar.init);
-    sinon.assert.calledOnce(baz.init);
-    sinon.assert.callOrder(bar.init, baz.init, foo.init);
-  });
-
-  it('throws meaningful error when required plugin is missing', async () => {
-    const plugins = [
-      {
-        id: 'foo',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: ['bar'],
-      },
-    ];
-
-    try {
-      await callPluginHook('init', plugins, 'foo', []);
-      throw new Error('expected callPluginHook to throw');
-    } catch (error) {
-      expect(error.message).toContain('"bar" for plugin "foo"');
-    }
-  });
-
-  it('throws meaningful error when dependencies are circular', async () => {
-    const plugins = [
-      {
-        id: 'foo',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: ['bar'],
-      },
-      {
-        id: 'bar',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: ['baz'],
-      },
-      {
-        id: 'baz',
-        init: sinon.spy(),
-        preInit: sinon.spy(),
-        requiredIds: ['foo'],
-      },
-    ];
-
-    try {
-      await callPluginHook('init', plugins, 'foo', []);
-      throw new Error('expected callPluginHook to throw');
-    } catch (error) {
-      expect(error.message).toContain('foo -> bar -> baz -> foo');
-    }
-  });
-});
diff --git a/src/legacy/server/plugins/lib/index.js b/src/legacy/server/plugins/lib/index.js
deleted file mode 100644
index 2329d24498b6b..0000000000000
--- a/src/legacy/server/plugins/lib/index.js
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { callPluginHook } from './call_plugin_hook';
-export { Plugin } from './plugin';
diff --git a/src/legacy/server/plugins/lib/plugin.js b/src/legacy/server/plugins/lib/plugin.js
deleted file mode 100644
index 48389061199ff..0000000000000
--- a/src/legacy/server/plugins/lib/plugin.js
+++ /dev/null
@@ -1,114 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { once } from 'lodash';
-
-/**
- * The server plugin class, used to extend the server
- * and add custom behavior. A "scoped" plugin class is
- * created by the PluginApi class and provided to plugin
- * providers that automatically binds all but the `opts`
- * arguments.
- *
- * @class Plugin
- * @param {KbnServer} kbnServer - the KbnServer this plugin
- *                              belongs to.
- * @param {PluginDefinition} def
- * @param {PluginSpec} spec
- */
-export class Plugin {
-  constructor(kbnServer, spec) {
-    this.kbnServer = kbnServer;
-    this.spec = spec;
-    this.pkg = spec.getPkg();
-    this.path = spec.getPath();
-    this.id = spec.getId();
-    this.version = spec.getVersion();
-    this.requiredIds = spec.getRequiredPluginIds() || [];
-    this.externalPreInit = spec.getPreInitHandler();
-    this.externalInit = spec.getInitHandler();
-    this.externalPostInit = spec.getPostInitHandler();
-    this.enabled = spec.isEnabled(kbnServer.config);
-    this.configPrefix = spec.getConfigPrefix();
-    this.publicDir = spec.getPublicDir();
-
-    this.preInit = once(this.preInit);
-    this.init = once(this.init);
-    this.postInit = once(this.postInit);
-  }
-
-  async preInit() {
-    if (this.externalPreInit) {
-      return await this.externalPreInit(this.kbnServer.server);
-    }
-  }
-
-  async init() {
-    const { id, version, kbnServer, configPrefix } = this;
-    const { config } = kbnServer;
-
-    // setup the hapi register function and get on with it
-    const register = async (server, options) => {
-      this._server = server;
-      this._options = options;
-
-      server.logWithMetadata(['plugins', 'debug'], `Initializing plugin ${this.toString()}`, {
-        plugin: this,
-      });
-
-      if (this.publicDir) {
-        server.newPlatform.__internals.http.registerStaticDir(
-          `/plugins/${id}/{path*}`,
-          this.publicDir
-        );
-      }
-
-      if (this.externalInit) {
-        await this.externalInit(server, options);
-      }
-    };
-
-    await kbnServer.server.register({
-      plugin: { register, name: id, version },
-      options: config.has(configPrefix) ? config.get(configPrefix) : null,
-    });
-  }
-
-  async postInit() {
-    if (this.externalPostInit) {
-      return await this.externalPostInit(this.kbnServer.server);
-    }
-  }
-
-  getServer() {
-    return this._server;
-  }
-
-  getOptions() {
-    return this._options;
-  }
-
-  toJSON() {
-    return this.pkg;
-  }
-
-  toString() {
-    return `${this.id}@${this.version}`;
-  }
-}
diff --git a/src/legacy/server/plugins/scan_mixin.js b/src/legacy/server/plugins/scan_mixin.js
deleted file mode 100644
index 89ebaf920d9d1..0000000000000
--- a/src/legacy/server/plugins/scan_mixin.js
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-import { Plugin } from './lib';
-
-export async function scanMixin(kbnServer) {
-  kbnServer.plugins = kbnServer.pluginSpecs.map((spec) => new Plugin(kbnServer, spec));
-}
diff --git a/src/legacy/server/plugins/wait_for_plugins_init.js b/src/legacy/server/plugins/wait_for_plugins_init.js
deleted file mode 100644
index 144eb5ef803cc..0000000000000
--- a/src/legacy/server/plugins/wait_for_plugins_init.js
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- * Tracks the individual queue for each kbnServer, rather than attaching
- * it to the kbnServer object via a property or something
- * @type {WeakMap}
- */
-const queues = new WeakMap();
-
-export function waitForInitSetupMixin(kbnServer) {
-  queues.set(kbnServer, []);
-
-  kbnServer.afterPluginsInit = function (callback) {
-    const queue = queues.get(kbnServer);
-
-    if (!queue) {
-      throw new Error(
-        'Plugins have already initialized. Only use this method for setup logic that must wait for plugins to initialize.'
-      );
-    }
-
-    queue.push(callback);
-  };
-}
-
-export async function waitForInitResolveMixin(kbnServer, server, config) {
-  const queue = queues.get(kbnServer);
-  queues.set(kbnServer, null);
-
-  // only actually call the callbacks if we are really initializing
-  if (config.get('plugins.initialize')) {
-    for (const cb of queue) {
-      await cb();
-    }
-  }
-}
diff --git a/src/legacy/types.ts b/src/legacy/types.ts
deleted file mode 100644
index 43c9ac79538b1..0000000000000
--- a/src/legacy/types.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export * from './plugin_discovery/types';
diff --git a/src/legacy/ui/__tests__/fixtures/plugin_async_foo/index.js b/src/legacy/ui/__tests__/fixtures/plugin_async_foo/index.js
deleted file mode 100644
index afe618c6d3d9c..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/plugin_async_foo/index.js
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import Bluebird from 'bluebird';
-
-export default (kibana) =>
-  new kibana.Plugin({
-    config(Joi) {
-      return Joi.object()
-        .keys({
-          enabled: Joi.boolean().default(true),
-          delay: Joi.number().required(),
-          shared: Joi.string(),
-        })
-        .default();
-    },
-
-    uiExports: {
-      async injectDefaultVars(server, options) {
-        await Bluebird.delay(options.delay);
-        return { shared: options.shared };
-      },
-    },
-  });
diff --git a/src/legacy/ui/__tests__/fixtures/plugin_async_foo/package.json b/src/legacy/ui/__tests__/fixtures/plugin_async_foo/package.json
deleted file mode 100644
index fc1c8d8088f1b..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/plugin_async_foo/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "plugin_async_foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/ui/__tests__/fixtures/plugin_bar/index.js b/src/legacy/ui/__tests__/fixtures/plugin_bar/index.js
deleted file mode 100644
index 975a1dc7c92e7..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/plugin_bar/index.js
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default (kibana) =>
-  new kibana.Plugin({
-    config(Joi) {
-      return Joi.object()
-        .keys({
-          enabled: Joi.boolean().default(true),
-          shared: Joi.string(),
-        })
-        .default();
-    },
-
-    uiExports: {
-      injectDefaultVars(server, options) {
-        return { shared: options.shared };
-      },
-    },
-  });
diff --git a/src/legacy/ui/__tests__/fixtures/plugin_bar/package.json b/src/legacy/ui/__tests__/fixtures/plugin_bar/package.json
deleted file mode 100644
index f79b807990dca..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/plugin_bar/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "plugin_bar",
-  "version": "kibana"
-}
diff --git a/src/legacy/ui/__tests__/fixtures/plugin_foo/index.js b/src/legacy/ui/__tests__/fixtures/plugin_foo/index.js
deleted file mode 100644
index 975a1dc7c92e7..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/plugin_foo/index.js
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default (kibana) =>
-  new kibana.Plugin({
-    config(Joi) {
-      return Joi.object()
-        .keys({
-          enabled: Joi.boolean().default(true),
-          shared: Joi.string(),
-        })
-        .default();
-    },
-
-    uiExports: {
-      injectDefaultVars(server, options) {
-        return { shared: options.shared };
-      },
-    },
-  });
diff --git a/src/legacy/ui/__tests__/fixtures/plugin_foo/package.json b/src/legacy/ui/__tests__/fixtures/plugin_foo/package.json
deleted file mode 100644
index c1b7ddd35c9a2..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/plugin_foo/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "plugin_foo",
-  "version": "kibana"
-}
diff --git a/src/legacy/ui/__tests__/fixtures/test_app/index.js b/src/legacy/ui/__tests__/fixtures/test_app/index.js
deleted file mode 100644
index 3eddefd618ce0..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/test_app/index.js
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export default (kibana) =>
-  new kibana.Plugin({
-    uiExports: {
-      app: {
-        name: 'test_app',
-        main: 'plugins/test_app/index.js',
-      },
-
-      injectDefaultVars() {
-        return {
-          from_defaults: true,
-        };
-      },
-    },
-    init(server) {
-      server.injectUiAppVars('test_app', () => ({
-        from_test_app: true,
-      }));
-    },
-  });
diff --git a/src/legacy/ui/__tests__/fixtures/test_app/package.json b/src/legacy/ui/__tests__/fixtures/test_app/package.json
deleted file mode 100644
index 3aeb029e4f4cc..0000000000000
--- a/src/legacy/ui/__tests__/fixtures/test_app/package.json
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  "name": "test_app",
-  "version": "kibana"
-}
diff --git a/src/legacy/ui/index.js b/src/legacy/ui/index.js
index 05373fa5d1964..5c06cb4677347 100644
--- a/src/legacy/ui/index.js
+++ b/src/legacy/ui/index.js
@@ -18,4 +18,3 @@
  */
 
 export { uiMixin } from './ui_mixin';
-export { collectUiExports } from './ui_exports';
diff --git a/src/legacy/ui/ui_exports/README.md b/src/legacy/ui/ui_exports/README.md
deleted file mode 100644
index 7fb117b1c25b9..0000000000000
--- a/src/legacy/ui/ui_exports/README.md
+++ /dev/null
@@ -1,95 +0,0 @@
-# UI Exports
-
-When defining a Plugin, the `uiExports` key can be used to define a map of export types to values that will be used to configure the UI system. A common use for `uiExports` is `uiExports.app`, which defines the configuration of a [`UiApp`][UiApp] and teaches the UI System how to render, bundle and tell the user about an application.
-
-
-## `collectUiExports(pluginSpecs): { [type: string]: any }`
-
-This function produces the object commonly found at `kbnServer.uiExports`. This object is created by calling `collectPluginExports()` with a standard set of export type reducers and defaults for the UI System.
-
-### export type reducers
-
-The [`ui_export_types` module][UiExportTypes] defines the reducer used for each uiExports key (or `type`). The name of every export in [./ui_export_types/index.js][UiExportTypes] is a key that plugins can define in their `uiExports` specification and the value of those exports are reducers that `collectPluginExports()` will call to produce the merged result of all export specs.
-
-### example - UiApps
-
-Plugin authors can define a new UiApp in their plugin specification like so:
-
-```js
-// a single app export
-export default function (kibana) {
-  return new kibana.Plugin({
-    //...
-    uiExports: {
-      app: {
-        // uiApp spec options go here
-      }
-    }
-  })
-}
-
-// apps can also export multiple apps
-export default function (kibana) {
-  return new kibana.Plugin({
-    //...
-    uiExports: {
-      apps: [
-        { /* uiApp spec options */ },
-        { /* second uiApp spec options */ },
-      ]
-    }
-  })
-}
-```
-
-To handle this export type, the [ui_export_types][UiExportTypes] module exports two reducers, one named `app` and the other `apps`.
-
-```js
-export const app = ...
-export const apps = ...
-```
-
-These reducers are defined in [`ui_export_types/ui_apps`][UiAppExportType] and have the exact same definition:
-
-```js
-// `wrap()` produces a reducer by wrapping a base reducer with modifiers.
-// All but the last argument are modifiers that take a reducer and return
-// an alternate reducer to use in it's place.
-// 
-// Most wrappers call their target reducer with slightly different
-// arguments. This allows composing standard reducer modifications for
-// reuse, consistency, and easy reference (once you get the hang of it).
-wrap(
-  // calls the next reducer with the `type` set to `uiAppSpecs`, ignoring
-  // the key the plugin author used to define this spec ("app" or "apps"
-  // in this example)
-  alias('uiAppSpecs'),
-  
-  // calls the next reducer with the `spec` set to the result of calling
-  // `applySpecDefaults(spec, type, pluginSpec)` which merges some defaults
-  // from the `PluginSpec` because we want uiAppSpecs to be useful individually
-  mapSpec(applySpecDefaults),
-  
-  // writes this spec to `acc[type]` (`acc.uiAppSpecs` in this example since
-  // the type was set to `uiAppSpecs` by `alias()`). It does this by concatenating
-  // the current value and the spec into an array. If either item is already
-  // an array its items are added to the result individually. If either item
-  // is undefined it is ignored.
-  // 
-  // NOTE: since flatConcatAtType is last it isn't a wrapper, it's
-  // just a normal reducer
-  flatConcatAtType
-)
-```
-
-This reducer format was chosen so that it will be easier to look back at these reducers and see that `app` and `apps` export specs are written to `kbnServer.uiExports.uiAppSpecs`, with defaults applied, in an array.
-
-### defaults
-
-The [`ui_exports/ui_export_defaults`][UiExportDefaults] module defines the default shape of the uiExports object produced by `collectUiExports()`. The defaults generally describe the `uiExports` from the UI System itself, like default visTypes and such.
-
-[UiExportDefaults]: ./ui_export_defaults.js "uiExport defaults definition"
-[UiExportTypes]: ./ui_export_types/index.js "Index of default ui_export_types module"
-[UiAppExportType]: ./ui_export_types/ui_apps.js "UiApp extension type definition"
-[PluginSpec]: ../../plugin_discovery/plugin_spec/plugin_spec.js "PluginSpec class definition"
-[PluginDiscovery]: '../../plugin_discovery' "plugin_discovery module"
\ No newline at end of file
diff --git a/src/legacy/ui/ui_exports/collect_ui_exports.ts b/src/legacy/ui/ui_exports/collect_ui_exports.ts
deleted file mode 100644
index edb2a11dc0527..0000000000000
--- a/src/legacy/ui/ui_exports/collect_ui_exports.ts
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { LegacyUiExports } from '../../../core/server';
-
-// @ts-ignore
-import { UI_EXPORT_DEFAULTS } from './ui_export_defaults';
-// @ts-ignore
-import * as uiExportTypeReducers from './ui_export_types';
-// @ts-ignore
-import { reduceExportSpecs } from '../../plugin_discovery';
-
-export function collectUiExports(pluginSpecs: unknown[]): LegacyUiExports {
-  return reduceExportSpecs(pluginSpecs, uiExportTypeReducers, UI_EXPORT_DEFAULTS);
-}
diff --git a/src/legacy/ui/ui_exports/index.js b/src/legacy/ui/ui_exports/index.js
deleted file mode 100644
index 56db698dc7b03..0000000000000
--- a/src/legacy/ui/ui_exports/index.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { collectUiExports } from './collect_ui_exports';
diff --git a/src/legacy/ui/ui_exports/ui_export_defaults.js b/src/legacy/ui/ui_exports/ui_export_defaults.js
deleted file mode 100644
index 227954155ce88..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_defaults.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export const UI_EXPORT_DEFAULTS = {};
diff --git a/src/legacy/ui/ui_exports/ui_export_types/index.js b/src/legacy/ui/ui_exports/ui_export_types/index.js
deleted file mode 100644
index 9ff6a53f4afb9..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/index.js
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { injectDefaultVars, replaceInjectedVars } from './modify_injected_vars';
-
-export {
-  mappings,
-  migrations,
-  savedObjectSchemas,
-  savedObjectsManagement,
-  validations,
-} from './saved_object';
-
-export { taskDefinitions } from './task_definitions';
-
-export { link, links } from './ui_nav_links';
-
-export { uiSettingDefaults } from './ui_settings';
-
-export { unknown } from './unknown';
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_injected_vars.js b/src/legacy/ui/ui_exports/ui_export_types/modify_injected_vars.js
deleted file mode 100644
index 4bb9f350bd959..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_injected_vars.js
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { flatConcatAtType } from './reduce';
-import { wrap, alias, mapSpec } from './modify_reduce';
-
-export const replaceInjectedVars = wrap(alias('injectedVarsReplacers'), flatConcatAtType);
-
-export const injectDefaultVars = wrap(
-  alias('defaultInjectedVarProviders'),
-  mapSpec((spec, type, pluginSpec) => ({
-    pluginSpec,
-    fn: spec,
-  })),
-  flatConcatAtType
-);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/alias.js b/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/alias.js
deleted file mode 100644
index a894e59a03c81..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/alias.js
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- *  Creates a reducer wrapper which, when called with a reducer, creates a new
- *  reducer that replaces the `type` value with `newType` before delegating to
- *  the wrapped reducer
- *  @param  {String} newType
- *  @return {Function}
- */
-export const alias = (newType) => (next) => (acc, spec, type, pluginSpec) =>
-  next(acc, spec, newType, pluginSpec);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/debug.js b/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/debug.js
deleted file mode 100644
index c40bca59fe14c..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/debug.js
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { mapSpec } from './map_spec';
-
-/**
- *  Reducer wrapper which, replaces the `spec` with the details about the definition
- *  of that spec
- *  @type {Function}
- */
-export const debug = mapSpec((spec, type, pluginSpec) => ({
-  spec,
-  type,
-  pluginSpec,
-}));
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/index.js b/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/index.js
deleted file mode 100644
index 54c81fefdd08a..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/index.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { alias } from './alias';
-export { debug } from './debug';
-export { mapSpec } from './map_spec';
-export { wrap } from './wrap';
-export { uniqueKeys } from './unique_keys';
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/map_spec.js b/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/map_spec.js
deleted file mode 100644
index 5970c45e7445e..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/map_spec.js
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- *  Creates a reducer wrapper which, when called with a reducer, creates a new
- *  reducer that replaces the `specs` value with the result of calling
- *  `mapFn(spec, type, pluginSpec)` before delegating to the wrapped
- *  reducer
- *  @param  {Function} mapFn receives `(specs, type, pluginSpec)`
- *  @return {Function}
- */
-export const mapSpec = (mapFn) => (next) => (acc, spec, type, pluginSpec) =>
-  next(acc, mapFn(spec, type, pluginSpec), type, pluginSpec);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/unique_keys.js b/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/unique_keys.js
deleted file mode 100644
index dedcd057b09e3..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/unique_keys.js
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-const pluginId = (pluginSpec) => (pluginSpec.id ? pluginSpec.id() : pluginSpec.getId());
-
-export const uniqueKeys = (sourceType) => (next) => (acc, spec, type, pluginSpec) => {
-  const duplicates = Object.keys(spec).filter((key) => acc[type] && acc[type].hasOwnProperty(key));
-
-  if (duplicates.length) {
-    throw new Error(
-      `${pluginId(pluginSpec)} defined duplicate ${sourceType || type} values: ${duplicates}`
-    );
-  }
-
-  return next(acc, spec, type, pluginSpec);
-};
diff --git a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/wrap.js b/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/wrap.js
deleted file mode 100644
index f84d83ed7c845..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/modify_reduce/wrap.js
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- *  Wrap a function with any number of wrappers. Wrappers
- *  are functions that take a reducer and return a reducer
- *  that should be called in its place. The wrappers will
- *  be called in reverse order for setup and then in the
- *  order they are defined when the resulting reducer is
- *  executed.
- *
- *  const reducer = wrap(
- *    next => (acc) => acc[1] = 'a',
- *    next => (acc) => acc[1] = 'b',
- *    next => (acc) => acc[1] = 'c'
- *  )
- *
- *  reducer('foo') //=> 'fco'
- *
- *  @param  {Function} ...wrappers
- *  @param  {Function} reducer
- *  @return {Function}
- */
-export function wrap(...args) {
-  const reducer = args[args.length - 1];
-  const wrappers = args.slice(0, -1);
-
-  return wrappers.reverse().reduce((acc, wrapper) => wrapper(acc), reducer);
-}
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/flat_concat_at_type.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/flat_concat_at_type.js
deleted file mode 100644
index 5fcbcac463392..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/flat_concat_at_type.js
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { createTypeReducer, flatConcat } from './lib';
-
-/**
- *  Reducer that merges two values concatenating all values
- *  into a flattened array
- *  @param  {Any} [initial]
- *  @return {Function}
- */
-export const flatConcatAtType = createTypeReducer(flatConcat);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/flat_concat_values_at_type.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/flat_concat_values_at_type.js
deleted file mode 100644
index 229c5be24aac5..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/flat_concat_values_at_type.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { createTypeReducer, flatConcat, mergeWith } from './lib';
-
-/**
- *  Reducer that merges specs by concatenating the values of
- *  all keys in accumulator and spec with the same logic as concat
- *  @param  {[type]} initial [description]
- *  @return {[type]}         [description]
- */
-export const flatConcatValuesAtType = createTypeReducer((objectA, objectB) =>
-  mergeWith(objectA || {}, objectB || {}, flatConcat)
-);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/index.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/index.js
deleted file mode 100644
index 7dc1ba60fb3cb..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/index.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { mergeAtType } from './merge_at_type';
-export { flatConcatValuesAtType } from './flat_concat_values_at_type';
-export { flatConcatAtType } from './flat_concat_at_type';
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/create_type_reducer.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/create_type_reducer.js
deleted file mode 100644
index bf4793c208308..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/create_type_reducer.js
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- *  Creates a reducer that reduces the values within `acc[type]` by calling
- *  reducer with signature:
- *
- *     reducer(acc[type], spec, type, pluginSpec)
- *
- *  @param  {Function} reducer
- *  @return {Function}
- */
-export const createTypeReducer = (reducer) => (acc, spec, type, pluginSpec) => ({
-  ...acc,
-  [type]: reducer(acc[type], spec, type, pluginSpec),
-});
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/flat_concat.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/flat_concat.js
deleted file mode 100644
index 1337c8a85d5b4..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/flat_concat.js
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-/**
- * Concatenate two values into a single array, ignoring either
- * value if it is undefined and flattening the value if it is an array
- * @param  {Array<T>|T} a
- * @param  {Array<T>} b
- * @return {Array<T>}
- */
-export const flatConcat = (a, b) => [].concat(a === undefined ? [] : a, b === undefined ? [] : b);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/index.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/index.js
deleted file mode 100644
index e4281caebe245..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/index.js
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-export { flatConcat } from './flat_concat';
-export { mergeWith } from './merge_with';
-export { createTypeReducer } from './create_type_reducer';
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/merge_with.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/merge_with.js
deleted file mode 100644
index 6c7d31e6fd74d..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/lib/merge_with.js
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-const uniqueConcat = (arrayA, arrayB) =>
-  arrayB.reduce((acc, key) => (acc.includes(key) ? acc : acc.concat(key)), arrayA);
-
-/**
- * Assign the keys from both objA and objB to target after passing the
- * current and new value through merge as `(target[key], source[key])`
- * @param  {Object} objA
- * @param  {Object} objB
- * @param  {Function} merge
- * @return {Object} target
- */
-export function mergeWith(objA, objB, merge) {
-  const target = {};
-  const keys = uniqueConcat(Object.keys(objA), Object.keys(objB));
-  for (const key of keys) {
-    target[key] = merge(objA[key], objB[key]);
-  }
-  return target;
-}
diff --git a/src/legacy/ui/ui_exports/ui_export_types/reduce/merge_at_type.js b/src/legacy/ui/ui_exports/ui_export_types/reduce/merge_at_type.js
deleted file mode 100644
index 4f5a501253851..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/reduce/merge_at_type.js
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { createTypeReducer } from './lib';
-
-export const mergeAtType = createTypeReducer((a, b) => ({
-  ...a,
-  ...b,
-}));
diff --git a/src/legacy/ui/ui_exports/ui_export_types/saved_object.js b/src/legacy/ui/ui_exports/ui_export_types/saved_object.js
deleted file mode 100644
index be6898d3e642c..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/saved_object.js
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { flatConcatAtType, mergeAtType } from './reduce';
-import { alias, mapSpec, uniqueKeys, wrap } from './modify_reduce';
-
-// mapping types
-export const mappings = wrap(
-  alias('savedObjectMappings'),
-  mapSpec((spec, type, pluginSpec) => ({
-    pluginId: pluginSpec.getId(),
-    properties: spec,
-  })),
-  flatConcatAtType
-);
-
-const pluginId = (pluginSpec) => (pluginSpec.id ? pluginSpec.id() : pluginSpec.getId());
-
-// Combines the `migrations` property of each plugin,
-// ensuring that properties are unique across plugins
-// and has migrations defined where the mappings are defined.
-// See saved_objects/migrations for more details.
-export const migrations = wrap(
-  alias('savedObjectMigrations'),
-  (next) => (acc, spec, type, pluginSpec) => {
-    const mappings = pluginSpec.getExportSpecs().mappings || {};
-    const invalidMigrationTypes = Object.keys(spec).filter((type) => !mappings[type]);
-    if (invalidMigrationTypes.length) {
-      throw new Error(
-        'Migrations and mappings must be defined together in the uiExports of a single plugin. ' +
-          `${pluginId(pluginSpec)} defines migrations for types ${invalidMigrationTypes.join(
-            ', '
-          )} but does not define their mappings.`
-      );
-    }
-    return next(acc, spec, type, pluginSpec);
-  },
-  uniqueKeys(),
-  mergeAtType
-);
-
-export const savedObjectSchemas = wrap(uniqueKeys(), mergeAtType);
-
-export const savedObjectsManagement = wrap(uniqueKeys(), mergeAtType);
-
-// Combines the `validations` property of each plugin,
-// ensuring that properties are unique across plugins.
-// See saved_objects/validation for more details.
-export const validations = wrap(alias('savedObjectValidations'), uniqueKeys(), mergeAtType);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/task_definitions.js b/src/legacy/ui/ui_exports/ui_export_types/task_definitions.js
deleted file mode 100644
index 8a0ed85d86f3e..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/task_definitions.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { mergeAtType } from './reduce';
-import { alias, wrap, uniqueKeys } from './modify_reduce';
-
-// How plugins define tasks that the task manager can run.
-export const taskDefinitions = wrap(alias('taskDefinitions'), uniqueKeys(), mergeAtType);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/ui_nav_links.js b/src/legacy/ui/ui_exports/ui_export_types/ui_nav_links.js
deleted file mode 100644
index 34aff7463a249..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/ui_nav_links.js
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { flatConcatAtType } from './reduce';
-import { wrap, alias } from './modify_reduce';
-
-export const links = wrap(alias('navLinkSpecs'), flatConcatAtType);
-export const link = wrap(alias('navLinkSpecs'), flatConcatAtType);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/ui_settings.js b/src/legacy/ui/ui_exports/ui_export_types/ui_settings.js
deleted file mode 100644
index 8d88490579c21..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/ui_settings.js
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { mergeAtType } from './reduce';
-import { wrap, uniqueKeys } from './modify_reduce';
-
-export const uiSettingDefaults = wrap(uniqueKeys(), mergeAtType);
diff --git a/src/legacy/ui/ui_exports/ui_export_types/unknown.js b/src/legacy/ui/ui_exports/ui_export_types/unknown.js
deleted file mode 100644
index a12a514d2e6bf..0000000000000
--- a/src/legacy/ui/ui_exports/ui_export_types/unknown.js
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { flatConcatAtType } from './reduce';
-import { wrap, alias, debug } from './modify_reduce';
-
-export const unknown = wrap(debug, alias('unknown'), flatConcatAtType);
diff --git a/src/legacy/ui/ui_render/ui_render_mixin.js b/src/legacy/ui/ui_render/ui_render_mixin.js
index e3b7c1e0c3ff9..2983dbbc28667 100644
--- a/src/legacy/ui/ui_render/ui_render_mixin.js
+++ b/src/legacy/ui/ui_render/ui_render_mixin.js
@@ -67,115 +67,108 @@ export function uiRenderMixin(kbnServer, server, config) {
     },
   });
 
-  // register the bootstrap.js route after plugins are initialized so that we can
-  // detect if any default auth strategies were registered
-  kbnServer.afterPluginsInit(() => {
-    const authEnabled = !!server.auth.settings.default;
-
-    server.route({
-      path: '/bootstrap.js',
-      method: 'GET',
-      config: {
-        tags: ['api'],
-        auth: authEnabled ? { mode: 'try' } : false,
-      },
-      async handler(request, h) {
-        const soClient = kbnServer.newPlatform.start.core.savedObjects.getScopedClient(
-          KibanaRequest.from(request)
-        );
-        const uiSettings = kbnServer.newPlatform.start.core.uiSettings.asScopedToClient(soClient);
-
-        const darkMode =
-          !authEnabled || request.auth.isAuthenticated
-            ? await uiSettings.get('theme:darkMode')
-            : false;
-
-        const themeVersion =
-          !authEnabled || request.auth.isAuthenticated
-            ? await uiSettings.get('theme:version')
-            : 'v7';
-
-        const themeTag = `${themeVersion === 'v7' ? 'v7' : 'v8'}${darkMode ? 'dark' : 'light'}`;
-
-        const buildHash = server.newPlatform.env.packageInfo.buildNum;
-        const basePath = config.get('server.basePath');
-
-        const regularBundlePath = `${basePath}/${buildHash}/bundles`;
-
-        const styleSheetPaths = [
-          `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.baseCssDistFilename}`,
-          ...(darkMode
-            ? [
-                themeVersion === 'v7'
-                  ? `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.darkCssDistFilename}`
-                  : `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.darkV8CssDistFilename}`,
-                `${basePath}/node_modules/@kbn/ui-framework/dist/kui_dark.css`,
-                `${basePath}/ui/legacy_dark_theme.css`,
-              ]
-            : [
-                themeVersion === 'v7'
-                  ? `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.lightCssDistFilename}`
-                  : `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.lightV8CssDistFilename}`,
-                `${basePath}/node_modules/@kbn/ui-framework/dist/kui_light.css`,
-                `${basePath}/ui/legacy_light_theme.css`,
-              ]),
-        ];
-
-        const kpUiPlugins = kbnServer.newPlatform.__internals.uiPlugins;
-        const kpPluginPublicPaths = new Map();
-        const kpPluginBundlePaths = new Set();
-
-        // recursively iterate over the kpUiPlugin ids and their required bundles
-        // to populate kpPluginPublicPaths and kpPluginBundlePaths
-        (function readKpPlugins(ids) {
-          for (const id of ids) {
-            if (kpPluginPublicPaths.has(id)) {
-              continue;
-            }
-
-            kpPluginPublicPaths.set(id, `${regularBundlePath}/plugin/${id}/`);
-            kpPluginBundlePaths.add(`${regularBundlePath}/plugin/${id}/${id}.plugin.js`);
-            readKpPlugins(kpUiPlugins.internal.get(id).requiredBundles);
+  const authEnabled = !!server.auth.settings.default;
+  server.route({
+    path: '/bootstrap.js',
+    method: 'GET',
+    config: {
+      tags: ['api'],
+      auth: authEnabled ? { mode: 'try' } : false,
+    },
+    async handler(request, h) {
+      const soClient = kbnServer.newPlatform.start.core.savedObjects.getScopedClient(
+        KibanaRequest.from(request)
+      );
+      const uiSettings = kbnServer.newPlatform.start.core.uiSettings.asScopedToClient(soClient);
+
+      const darkMode =
+        !authEnabled || request.auth.isAuthenticated
+          ? await uiSettings.get('theme:darkMode')
+          : false;
+
+      const themeVersion =
+        !authEnabled || request.auth.isAuthenticated ? await uiSettings.get('theme:version') : 'v7';
+
+      const themeTag = `${themeVersion === 'v7' ? 'v7' : 'v8'}${darkMode ? 'dark' : 'light'}`;
+
+      const buildHash = server.newPlatform.env.packageInfo.buildNum;
+      const basePath = config.get('server.basePath');
+
+      const regularBundlePath = `${basePath}/${buildHash}/bundles`;
+
+      const styleSheetPaths = [
+        `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.baseCssDistFilename}`,
+        ...(darkMode
+          ? [
+              themeVersion === 'v7'
+                ? `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.darkCssDistFilename}`
+                : `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.darkV8CssDistFilename}`,
+              `${basePath}/node_modules/@kbn/ui-framework/dist/kui_dark.css`,
+              `${basePath}/ui/legacy_dark_theme.css`,
+            ]
+          : [
+              themeVersion === 'v7'
+                ? `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.lightCssDistFilename}`
+                : `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.lightV8CssDistFilename}`,
+              `${basePath}/node_modules/@kbn/ui-framework/dist/kui_light.css`,
+              `${basePath}/ui/legacy_light_theme.css`,
+            ]),
+      ];
+
+      const kpUiPlugins = kbnServer.newPlatform.__internals.uiPlugins;
+      const kpPluginPublicPaths = new Map();
+      const kpPluginBundlePaths = new Set();
+
+      // recursively iterate over the kpUiPlugin ids and their required bundles
+      // to populate kpPluginPublicPaths and kpPluginBundlePaths
+      (function readKpPlugins(ids) {
+        for (const id of ids) {
+          if (kpPluginPublicPaths.has(id)) {
+            continue;
           }
-        })(kpUiPlugins.public.keys());
-
-        const jsDependencyPaths = [
-          ...UiSharedDeps.jsDepFilenames.map(
-            (filename) => `${regularBundlePath}/kbn-ui-shared-deps/${filename}`
-          ),
-          `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.jsFilename}`,
-
-          `${regularBundlePath}/core/core.entry.js`,
-          ...kpPluginBundlePaths,
-        ];
-
-        // These paths should align with the bundle routes configured in
-        // src/optimize/bundles_route/bundles_route.ts
-        const publicPathMap = JSON.stringify({
-          core: `${regularBundlePath}/core/`,
-          'kbn-ui-shared-deps': `${regularBundlePath}/kbn-ui-shared-deps/`,
-          ...Object.fromEntries(kpPluginPublicPaths),
-        });
-
-        const bootstrap = new AppBootstrap({
-          templateData: {
-            themeTag,
-            jsDependencyPaths,
-            styleSheetPaths,
-            publicPathMap,
-          },
-        });
-
-        const body = await bootstrap.getJsFile();
-        const etag = await bootstrap.getJsFileHash();
-
-        return h
-          .response(body)
-          .header('cache-control', 'must-revalidate')
-          .header('content-type', 'application/javascript')
-          .etag(etag);
-      },
-    });
+
+          kpPluginPublicPaths.set(id, `${regularBundlePath}/plugin/${id}/`);
+          kpPluginBundlePaths.add(`${regularBundlePath}/plugin/${id}/${id}.plugin.js`);
+          readKpPlugins(kpUiPlugins.internal.get(id).requiredBundles);
+        }
+      })(kpUiPlugins.public.keys());
+
+      const jsDependencyPaths = [
+        ...UiSharedDeps.jsDepFilenames.map(
+          (filename) => `${regularBundlePath}/kbn-ui-shared-deps/${filename}`
+        ),
+        `${regularBundlePath}/kbn-ui-shared-deps/${UiSharedDeps.jsFilename}`,
+
+        `${regularBundlePath}/core/core.entry.js`,
+        ...kpPluginBundlePaths,
+      ];
+
+      // These paths should align with the bundle routes configured in
+      // src/optimize/bundles_route/bundles_route.ts
+      const publicPathMap = JSON.stringify({
+        core: `${regularBundlePath}/core/`,
+        'kbn-ui-shared-deps': `${regularBundlePath}/kbn-ui-shared-deps/`,
+        ...Object.fromEntries(kpPluginPublicPaths),
+      });
+
+      const bootstrap = new AppBootstrap({
+        templateData: {
+          themeTag,
+          jsDependencyPaths,
+          styleSheetPaths,
+          publicPathMap,
+        },
+      });
+
+      const body = await bootstrap.getJsFile();
+      const etag = await bootstrap.getJsFileHash();
+
+      return h
+        .response(body)
+        .header('cache-control', 'must-revalidate')
+        .header('content-type', 'application/javascript')
+        .etag(etag);
+    },
   });
 
   server.route({
@@ -191,19 +184,17 @@ export function uiRenderMixin(kbnServer, server, config) {
   });
 
   async function renderApp(h) {
-    const app = { getId: () => 'core' };
     const { http } = kbnServer.newPlatform.setup.core;
     const { savedObjects } = kbnServer.newPlatform.start.core;
-    const { rendering, legacy } = kbnServer.newPlatform.__internals;
+    const { rendering } = kbnServer.newPlatform.__internals;
     const req = KibanaRequest.from(h.request);
     const uiSettings = kbnServer.newPlatform.start.core.uiSettings.asScopedToClient(
       savedObjects.getScopedClient(req)
     );
-    const vars = await legacy.getVars(app.getId(), h.request, {
+    const vars = {
       apmConfig: getApmConfig(h.request.path),
-    });
+    };
     const content = await rendering.render(h.request, uiSettings, {
-      app,
       includeUserSettings: true,
       vars,
     });
diff --git a/x-pack/.gitignore b/x-pack/.gitignore
index d73b6f64f036a..99e33dbb88e92 100644
--- a/x-pack/.gitignore
+++ b/x-pack/.gitignore
@@ -6,13 +6,9 @@
 /test/functional/apps/reporting/reports/session
 /test/reporting/configs/failure_debug/
 /plugins/reporting/.chromium/
-/legacy/plugins/reporting/.chromium/
-/legacy/plugins/reporting/.phantom/
 /plugins/reporting/chromium/
 /plugins/reporting/.phantom/
 /.aws-config.json
 /.env
 /.kibana-plugin-helpers.dev.*
-!/legacy/plugins/infra/**/target
 .cache
-!/legacy/plugins/security_solution/**/target
diff --git a/x-pack/.i18nrc.json b/x-pack/.i18nrc.json
index feae89cdb1867..53a2d8f2f6168 100644
--- a/x-pack/.i18nrc.json
+++ b/x-pack/.i18nrc.json
@@ -9,8 +9,8 @@
     "xpack.alerts": "plugins/alerts",
     "xpack.eventLog": "plugins/event_log",
     "xpack.alertingBuiltins": "plugins/alerting_builtins",
-    "xpack.apm": ["legacy/plugins/apm", "plugins/apm"],
-    "xpack.beatsManagement": ["legacy/plugins/beats_management", "plugins/beats_management"],
+    "xpack.apm": "plugins/apm",
+    "xpack.beatsManagement": "plugins/beats_management",
     "xpack.canvas": "plugins/canvas",
     "xpack.cloud": "plugins/cloud",
     "xpack.dashboard": "plugins/dashboard_enhanced",
@@ -35,15 +35,15 @@
     "xpack.lens": "plugins/lens",
     "xpack.licenseMgmt": "plugins/license_management",
     "xpack.licensing": "plugins/licensing",
-    "xpack.logstash": ["plugins/logstash", "legacy/plugins/logstash"],
-    "xpack.main": ["legacy/plugins/xpack_main", "plugins/xpack_legacy"],
-    "xpack.maps": ["plugins/maps", "legacy/plugins/maps"],
-    "xpack.ml": ["plugins/ml", "legacy/plugins/ml"],
+    "xpack.logstash": ["plugins/logstash"],
+    "xpack.main": ["plugins/xpack_legacy"],
+    "xpack.maps": ["plugins/maps"],
+    "xpack.ml": ["plugins/ml"],
     "xpack.monitoring": ["plugins/monitoring"],
     "xpack.remoteClusters": "plugins/remote_clusters",
     "xpack.painlessLab": "plugins/painless_lab",
     "xpack.reporting": ["plugins/reporting"],
-    "xpack.rollupJobs": ["legacy/plugins/rollup", "plugins/rollup"],
+    "xpack.rollupJobs": ["plugins/rollup"],
     "xpack.searchProfiler": "plugins/searchprofiler",
     "xpack.security": "plugins/security",
     "xpack.server": "legacy/server",
diff --git a/x-pack/dev-tools/jest/create_jest_config.js b/x-pack/dev-tools/jest/create_jest_config.js
index 0a5cc9753aadd..744e119126a62 100644
--- a/x-pack/dev-tools/jest/create_jest_config.js
+++ b/x-pack/dev-tools/jest/create_jest_config.js
@@ -8,17 +8,15 @@ export function createJestConfig({ kibanaDirectory, rootDir, xPackKibanaDirector
   const fileMockPath = `${kibanaDirectory}/src/dev/jest/mocks/file_mock.js`;
   return {
     rootDir,
-    roots: ['<rootDir>/plugins', '<rootDir>/legacy/plugins', '<rootDir>/legacy/server'],
+    roots: ['<rootDir>/plugins'],
     moduleFileExtensions: ['js', 'mjs', 'json', 'ts', 'tsx', 'node'],
     moduleNameMapper: {
       '@elastic/eui$': `${kibanaDirectory}/node_modules/@elastic/eui/test-env`,
       '@elastic/eui/lib/(.*)?': `${kibanaDirectory}/node_modules/@elastic/eui/test-env/$1`,
       '^fixtures/(.*)': `${kibanaDirectory}/src/fixtures/$1`,
-      'uiExports/(.*)': fileMockPath,
       '^src/core/(.*)': `${kibanaDirectory}/src/core/$1`,
       '^src/legacy/(.*)': `${kibanaDirectory}/src/legacy/$1`,
       '^src/plugins/(.*)': `${kibanaDirectory}/src/plugins/$1`,
-      '^plugins/xpack_main/(.*);': `${xPackKibanaDirectory}/legacy/plugins/xpack_main/public/$1`,
       '\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$': fileMockPath,
       '\\.module.(css|scss)$': `${kibanaDirectory}/src/dev/jest/mocks/css_module_mock.js`,
       '\\.(css|less|scss)$': `${kibanaDirectory}/src/dev/jest/mocks/style_mock.js`,
@@ -32,8 +30,6 @@ export function createJestConfig({ kibanaDirectory, rootDir, xPackKibanaDirector
     coverageDirectory: `${kibanaDirectory}/target/kibana-coverage/jest`,
     coverageReporters: ['html'],
     collectCoverageFrom: [
-      'legacy/plugins/**/*.{js,mjs,jsx,ts,tsx}',
-      'legacy/server/**/*.{js,mjs,jsx,ts,tsx}',
       'plugins/**/*.{js,mjs,jsx,ts,tsx}',
       '!**/{__test__,__snapshots__,__examples__,integration_tests,tests}/**',
       '!**/*.test.{js,mjs,ts,tsx}',
diff --git a/x-pack/index.js b/x-pack/index.js
deleted file mode 100644
index cb68004c26d65..0000000000000
--- a/x-pack/index.js
+++ /dev/null
@@ -1,11 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { xpackMain } from './legacy/plugins/xpack_main';
-
-module.exports = function (kibana) {
-  return [xpackMain(kibana)];
-};
diff --git a/x-pack/legacy/common/__tests__/poller.js b/x-pack/legacy/common/__tests__/poller.js
deleted file mode 100644
index 24558502a8d02..0000000000000
--- a/x-pack/legacy/common/__tests__/poller.js
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import sinon from 'sinon';
-import { Poller } from '../poller';
-
-describe('Poller', () => {
-  const pollFrequencyInMillis = 20;
-  let functionToPoll;
-  let successFunction;
-  let errorFunction;
-  let poller;
-  let clock;
-
-  beforeEach(() => {
-    clock = sinon.useFakeTimers();
-  });
-
-  afterEach(() => {
-    clock.restore();
-    if (poller) {
-      poller.stop();
-    }
-  });
-
-  // Allowing the Poller to poll requires intimate knowledge of the inner workings of the Poller.
-  // We have to ensure that the Promises internal to the `_poll` method are resolved to queue up
-  // the next setTimeout before incrementing the clock. The order of this differs slightly when the
-  // `trailing` is set, hence the different `allowPoll` and `allowDelayPoll` functions.
-  const queueNextPoll = async () => {
-    await Promise.resolve();
-    await Promise.resolve();
-  };
-
-  const allowPoll = async (interval) => {
-    await queueNextPoll();
-    clock.tick(interval);
-  };
-
-  const allowDelayPoll = async (interval) => {
-    clock.tick(interval);
-    await queueNextPoll();
-  };
-
-  describe('start()', () => {
-    beforeEach(() => {
-      functionToPoll = sinon.spy(() => {
-        return Promise.resolve(42);
-      });
-      successFunction = sinon.spy();
-      errorFunction = sinon.spy();
-      poller = new Poller({
-        functionToPoll,
-        successFunction,
-        errorFunction,
-        pollFrequencyInMillis,
-      });
-    });
-
-    describe(`when trailing isn't set`, () => {
-      it(`polls immediately`, () => {
-        poller.start();
-        expect(functionToPoll.callCount).to.be(1);
-      });
-    });
-
-    describe(`when trailing is set to true`, () => {
-      beforeEach(() => {
-        poller = new Poller({
-          functionToPoll,
-          successFunction,
-          errorFunction,
-          pollFrequencyInMillis,
-          trailing: true,
-        });
-      });
-
-      it('waits for pollFrequencyInMillis before polling', async () => {
-        poller.start();
-        expect(functionToPoll.callCount).to.be(0);
-        allowDelayPoll(pollFrequencyInMillis);
-        expect(functionToPoll.callCount).to.be(1);
-      });
-    });
-
-    it('polls the functionToPoll multiple times', async () => {
-      poller.start();
-      await allowPoll(pollFrequencyInMillis * 2);
-      expect(functionToPoll.callCount).to.be.greaterThan(1);
-    });
-
-    describe('when the function to poll succeeds', () => {
-      it('calls the successFunction multiple times', async () => {
-        poller.start();
-        await allowPoll(pollFrequencyInMillis * 2);
-        expect(successFunction.callCount).to.be.greaterThan(1);
-        expect(errorFunction.callCount).to.be(0);
-      });
-    });
-
-    describe('when the function to poll fails', () => {
-      beforeEach(() => {
-        functionToPoll = sinon.spy(() => {
-          return Promise.reject(42);
-        });
-      });
-
-      describe('when the continuePollingOnError option has not been set', () => {
-        beforeEach(() => {
-          poller = new Poller({
-            functionToPoll,
-            successFunction,
-            errorFunction,
-            pollFrequencyInMillis,
-          });
-        });
-
-        it('calls the errorFunction exactly once and polling is stopped', async () => {
-          poller.start();
-          await allowPoll(pollFrequencyInMillis * 4);
-          expect(poller.isRunning()).to.be(false);
-          expect(successFunction.callCount).to.be(0);
-          expect(errorFunction.callCount).to.be(1);
-        });
-      });
-
-      describe('when the continuePollingOnError option has been set to true', () => {
-        beforeEach(() => {
-          poller = new Poller({
-            functionToPoll,
-            successFunction,
-            errorFunction,
-            pollFrequencyInMillis,
-            continuePollingOnError: true,
-          });
-        });
-
-        it('calls the errorFunction multiple times', async () => {
-          poller.start();
-          await allowPoll(pollFrequencyInMillis);
-          await allowPoll(pollFrequencyInMillis);
-          expect(successFunction.callCount).to.be(0);
-          expect(errorFunction.callCount).to.be.greaterThan(1);
-        });
-
-        describe('when pollFrequencyErrorMultiplier has been set', () => {
-          beforeEach(() => {
-            poller = new Poller({
-              functionToPoll,
-              successFunction,
-              errorFunction,
-              pollFrequencyInMillis,
-              continuePollingOnError: true,
-              pollFrequencyErrorMultiplier: 2,
-            });
-          });
-
-          it('waits for the multiplier * the pollFrequency', async () => {
-            poller.start();
-            await queueNextPoll();
-            expect(functionToPoll.callCount).to.be(1);
-            await allowPoll(pollFrequencyInMillis);
-            expect(functionToPoll.callCount).to.be(1);
-            await allowPoll(pollFrequencyInMillis);
-            expect(functionToPoll.callCount).to.be(2);
-          });
-        });
-      });
-    });
-  });
-
-  describe('isRunning()', () => {
-    beforeEach(() => {
-      functionToPoll = sinon.spy(() => {
-        return Promise.resolve(42);
-      });
-      poller = new Poller({
-        functionToPoll,
-      });
-    });
-
-    it('returns true immediately after invoking start()', () => {
-      poller.start();
-      expect(poller.isRunning()).to.be(true);
-    });
-
-    it('returns false after invoking stop', () => {
-      poller.start();
-      poller.stop();
-      expect(poller.isRunning()).to.be(false);
-    });
-  });
-
-  describe('stop()', () => {
-    describe(`when successFunction isn't set`, () => {
-      beforeEach(() => {
-        functionToPoll = sinon.spy(() => {
-          return Promise.resolve(42);
-        });
-        poller = new Poller({
-          functionToPoll,
-          pollFrequencyInMillis,
-        });
-      });
-
-      it(`doesn't poll again`, async () => {
-        poller.start();
-        expect(functionToPoll.callCount).to.be(1);
-        poller.stop();
-        await allowPoll(pollFrequencyInMillis);
-        expect(functionToPoll.callCount).to.be(1);
-      });
-    });
-
-    describe(`when successFunction is a Promise`, () => {
-      beforeEach(() => {
-        functionToPoll = sinon.spy(() => {
-          return Promise.resolve(42);
-        });
-        poller = new Poller({
-          functionToPoll,
-          successFunction: Promise.resolve(),
-          pollFrequencyInMillis,
-        });
-      });
-
-      it(`doesn't poll again when successFunction is a Promise`, async () => {
-        poller.start();
-        expect(functionToPoll.callCount).to.be(1);
-        poller.stop();
-        await allowPoll(pollFrequencyInMillis);
-        expect(functionToPoll.callCount).to.be(1);
-      });
-    });
-  });
-});
diff --git a/x-pack/legacy/common/constants/index.ts b/x-pack/legacy/common/constants/index.ts
deleted file mode 100644
index 4db0f994fd47e..0000000000000
--- a/x-pack/legacy/common/constants/index.ts
+++ /dev/null
@@ -1,23 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export {
-  LICENSE_STATUS_UNAVAILABLE,
-  LICENSE_STATUS_INVALID,
-  LICENSE_STATUS_EXPIRED,
-  LICENSE_STATUS_VALID,
-} from './license_status';
-
-export {
-  LICENSE_TYPE_BASIC,
-  LICENSE_TYPE_STANDARD,
-  LICENSE_TYPE_GOLD,
-  LICENSE_TYPE_PLATINUM,
-  LICENSE_TYPE_ENTERPRISE,
-  LICENSE_TYPE_TRIAL,
-  RANKED_LICENSE_TYPES,
-  LicenseType,
-} from './license_types';
diff --git a/x-pack/legacy/common/constants/license_status.ts b/x-pack/legacy/common/constants/license_status.ts
deleted file mode 100644
index 5fdfa08d73959..0000000000000
--- a/x-pack/legacy/common/constants/license_status.ts
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export const LICENSE_STATUS_UNAVAILABLE = 'UNAVAILABLE';
-export const LICENSE_STATUS_INVALID = 'INVALID';
-export const LICENSE_STATUS_EXPIRED = 'EXPIRED';
-export const LICENSE_STATUS_VALID = 'VALID';
diff --git a/x-pack/legacy/common/constants/license_types.ts b/x-pack/legacy/common/constants/license_types.ts
deleted file mode 100644
index 8c329df2f85f7..0000000000000
--- a/x-pack/legacy/common/constants/license_types.ts
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export const LICENSE_TYPE_BASIC = 'basic';
-export const LICENSE_TYPE_STANDARD = 'standard';
-export const LICENSE_TYPE_GOLD = 'gold';
-export const LICENSE_TYPE_PLATINUM = 'platinum';
-export const LICENSE_TYPE_ENTERPRISE = 'enterprise';
-export const LICENSE_TYPE_TRIAL = 'trial';
-
-export type LicenseType =
-  | typeof LICENSE_TYPE_BASIC
-  | typeof LICENSE_TYPE_STANDARD
-  | typeof LICENSE_TYPE_GOLD
-  | typeof LICENSE_TYPE_PLATINUM
-  | typeof LICENSE_TYPE_ENTERPRISE
-  | typeof LICENSE_TYPE_TRIAL;
-
-// These are ordered from least featureful to most featureful, so we can assume that someone holding
-// a license at a particular index cannot access any features unlocked by the licenses that follow it.
-export const RANKED_LICENSE_TYPES = [
-  LICENSE_TYPE_BASIC,
-  LICENSE_TYPE_STANDARD,
-  LICENSE_TYPE_GOLD,
-  LICENSE_TYPE_PLATINUM,
-  LICENSE_TYPE_ENTERPRISE,
-  LICENSE_TYPE_TRIAL,
-];
diff --git a/x-pack/legacy/common/eui_draggable/index.d.ts b/x-pack/legacy/common/eui_draggable/index.d.ts
deleted file mode 100644
index 322966b3c982e..0000000000000
--- a/x-pack/legacy/common/eui_draggable/index.d.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import React from 'react';
-import { EuiDraggable, EuiDragDropContext } from '@elastic/eui';
-
-type PropsOf<T> = T extends React.ComponentType<infer ComponentProps> ? ComponentProps : never;
-type FirstArgumentOf<Func> = Func extends (arg1: infer FirstArgument, ...rest: any[]) => any
-  ? FirstArgument
-  : never;
-export type DragHandleProps = FirstArgumentOf<
-  Exclude<PropsOf<typeof EuiDraggable>['children'], React.ReactElement>
->['dragHandleProps'];
-export type DropResult = FirstArgumentOf<FirstArgumentOf<typeof EuiDragDropContext>['onDragEnd']>;
diff --git a/x-pack/legacy/common/eui_styled_components/index.ts b/x-pack/legacy/common/eui_styled_components/index.ts
deleted file mode 100644
index 9b3ed903627b4..0000000000000
--- a/x-pack/legacy/common/eui_styled_components/index.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import {
-  css,
-  euiStyled,
-  EuiTheme,
-  EuiThemeProvider,
-  createGlobalStyle,
-  keyframes,
-  withTheme,
-} from './eui_styled_components';
-
-export { css, euiStyled, EuiTheme, EuiThemeProvider, createGlobalStyle, keyframes, withTheme };
-// In order to to mimic the styled-components module we need to ignore the following
-// eslint-disable-next-line import/no-default-export
-export default euiStyled;
diff --git a/x-pack/legacy/common/poller.d.ts b/x-pack/legacy/common/poller.d.ts
deleted file mode 100644
index df39d93a28a81..0000000000000
--- a/x-pack/legacy/common/poller.d.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export declare class Poller {
-  constructor(options: any);
-
-  public start(): void;
-  public stop(): void;
-  public isRunning(): boolean;
-  public getPollFrequency(): number;
-}
diff --git a/x-pack/legacy/common/poller.js b/x-pack/legacy/common/poller.js
deleted file mode 100644
index 09824ce9d6d23..0000000000000
--- a/x-pack/legacy/common/poller.js
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import _ from 'lodash';
-
-export class Poller {
-  constructor(options) {
-    this.functionToPoll = options.functionToPoll; // Must return a Promise
-    this.successFunction = options.successFunction || _.noop;
-    this.errorFunction = options.errorFunction || _.noop;
-    this.pollFrequencyInMillis = options.pollFrequencyInMillis;
-    this.trailing = options.trailing || false;
-    this.continuePollingOnError = options.continuePollingOnError || false;
-    this.pollFrequencyErrorMultiplier = options.pollFrequencyErrorMultiplier || 1;
-    this._timeoutId = null;
-    this._isRunning = false;
-  }
-
-  getPollFrequency() {
-    return this.pollFrequencyInMillis;
-  }
-
-  _poll() {
-    return this.functionToPoll()
-      .then(this.successFunction)
-      .then(() => {
-        if (!this._isRunning) {
-          return;
-        }
-
-        this._timeoutId = setTimeout(this._poll.bind(this), this.pollFrequencyInMillis);
-      })
-      .catch((e) => {
-        this.errorFunction(e);
-        if (!this._isRunning) {
-          return;
-        }
-
-        if (this.continuePollingOnError) {
-          this._timeoutId = setTimeout(
-            this._poll.bind(this),
-            this.pollFrequencyInMillis * this.pollFrequencyErrorMultiplier
-          );
-        } else {
-          this.stop();
-        }
-      });
-  }
-
-  start() {
-    if (this._isRunning) {
-      return;
-    }
-
-    this._isRunning = true;
-    if (this.trailing) {
-      this._timeoutId = setTimeout(this._poll.bind(this), this.pollFrequencyInMillis);
-    } else {
-      this._poll();
-    }
-  }
-
-  stop() {
-    if (!this._isRunning) {
-      return;
-    }
-
-    this._isRunning = false;
-    clearTimeout(this._timeoutId);
-    this._timeoutId = null;
-  }
-
-  isRunning() {
-    return this._isRunning;
-  }
-}
diff --git a/x-pack/legacy/plugins/xpack_main/index.js b/x-pack/legacy/plugins/xpack_main/index.js
deleted file mode 100644
index 2ed32efb675db..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/index.js
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { resolve } from 'path';
-import { setupXPackMain } from './server/lib/setup_xpack_main';
-import { xpackInfoRoute } from './server/routes/api/v1';
-
-export const xpackMain = (kibana) => {
-  return new kibana.Plugin({
-    id: 'xpack_main',
-    configPrefix: 'xpack.xpack_main',
-    publicDir: resolve(__dirname, 'public'),
-    require: [],
-
-    config(Joi) {
-      return Joi.object({
-        enabled: Joi.boolean().default(true),
-        telemetry: Joi.object({
-          config: Joi.string().default(),
-          enabled: Joi.boolean().default(),
-          url: Joi.string().default(),
-        }).default(), // deprecated
-      }).default();
-    },
-
-    init(server) {
-      setupXPackMain(server);
-
-      // register routes
-      xpackInfoRoute(server);
-    },
-  });
-};
diff --git a/x-pack/legacy/plugins/xpack_main/server/lib/__tests__/setup_xpack_main.js b/x-pack/legacy/plugins/xpack_main/server/lib/__tests__/setup_xpack_main.js
deleted file mode 100644
index f49f44bed97a7..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/lib/__tests__/setup_xpack_main.js
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { BehaviorSubject } from 'rxjs';
-import sinon from 'sinon';
-import { XPackInfo } from '../xpack_info';
-import { setupXPackMain } from '../setup_xpack_main';
-
-describe('setupXPackMain()', () => {
-  const sandbox = sinon.createSandbox();
-
-  let mockServer;
-  let mockStatusObservable;
-  let mockElasticsearchPlugin;
-
-  beforeEach(() => {
-    sandbox.useFakeTimers();
-
-    mockElasticsearchPlugin = {
-      getCluster: sinon.stub(),
-    };
-
-    mockStatusObservable = sinon.stub({ subscribe() {} });
-
-    mockServer = sinon.stub({
-      plugins: {
-        elasticsearch: mockElasticsearchPlugin,
-      },
-      newPlatform: {
-        setup: {
-          core: {
-            status: {
-              core$: {
-                pipe() {
-                  return mockStatusObservable;
-                },
-              },
-            },
-          },
-          plugins: { features: {}, licensing: { license$: new BehaviorSubject() } },
-        },
-      },
-      events: { on() {} },
-      log() {},
-      config() {},
-      expose() {},
-      ext() {},
-    });
-
-    // Make sure plugins doesn't consume config
-    const configGetStub = sinon
-      .stub()
-      .throws(new Error('`config.get` is called with unexpected key.'));
-    mockServer.config.returns({ get: configGetStub });
-  });
-
-  afterEach(() => sandbox.restore());
-
-  it('all extension hooks should be properly initialized.', () => {
-    setupXPackMain(mockServer);
-
-    sinon.assert.calledWithExactly(mockServer.expose, 'info', sinon.match.instanceOf(XPackInfo));
-    sinon.assert.calledWithExactly(mockStatusObservable.subscribe, sinon.match.func);
-  });
-});
diff --git a/x-pack/legacy/plugins/xpack_main/server/lib/__tests__/xpack_info.js b/x-pack/legacy/plugins/xpack_main/server/lib/__tests__/xpack_info.js
deleted file mode 100644
index 81fb822882817..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/lib/__tests__/xpack_info.js
+++ /dev/null
@@ -1,398 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { createHash } from 'crypto';
-import { BehaviorSubject } from 'rxjs';
-import expect from '@kbn/expect';
-import sinon from 'sinon';
-import { XPackInfo } from '../xpack_info';
-import { licensingMock } from '../../../../../../plugins/licensing/server/mocks';
-
-function createLicense(license = {}, features = {}) {
-  return licensingMock.createLicense({
-    license: {
-      uid: 'custom-uid',
-      type: 'gold',
-      mode: 'gold',
-      status: 'active',
-      expiryDateInMillis: 1286575200000,
-      ...license,
-    },
-    features: {
-      security: {
-        description: 'Security for the Elastic Stack',
-        isAvailable: true,
-        isEnabled: true,
-      },
-      watcher: {
-        description: 'Alerting, Notification and Automation for the Elastic Stack',
-        isAvailable: true,
-        isEnabled: false,
-      },
-      ...features,
-    },
-  });
-}
-
-function getSignature(object) {
-  return createHash('md5').update(JSON.stringify(object)).digest('hex');
-}
-
-describe('XPackInfo', () => {
-  let mockServer;
-  let mockElasticsearchPlugin;
-
-  beforeEach(() => {
-    mockServer = sinon.stub({
-      plugins: { elasticsearch: mockElasticsearchPlugin },
-      events: { on() {} },
-      newPlatform: {
-        setup: {
-          plugins: {
-            licensing: {},
-          },
-        },
-      },
-    });
-  });
-
-  describe('refreshNow()', () => {
-    it('delegates to the new platform licensing plugin', async () => {
-      const refresh = sinon.spy();
-
-      const xPackInfo = new XPackInfo(mockServer, {
-        licensing: {
-          license$: new BehaviorSubject(createLicense()),
-          refresh: refresh,
-        },
-      });
-
-      await xPackInfo.refreshNow();
-
-      sinon.assert.calledOnce(refresh);
-    });
-  });
-
-  describe('license', () => {
-    let xPackInfo;
-    let license$;
-    beforeEach(async () => {
-      license$ = new BehaviorSubject(createLicense());
-      xPackInfo = new XPackInfo(mockServer, {
-        licensing: {
-          license$,
-          refresh: () => null,
-        },
-      });
-    });
-
-    it('getUid() shows license uid returned from the license$.', async () => {
-      expect(xPackInfo.license.getUid()).to.be('custom-uid');
-
-      license$.next(createLicense({ uid: 'new-custom-uid' }));
-
-      expect(xPackInfo.license.getUid()).to.be('new-custom-uid');
-
-      license$.next(createLicense({ uid: undefined, error: 'error-reason' }));
-
-      expect(xPackInfo.license.getUid()).to.be(undefined);
-    });
-
-    it('isActive() is based on the status returned from the backend.', async () => {
-      expect(xPackInfo.license.isActive()).to.be(true);
-
-      license$.next(createLicense({ status: 'expired' }));
-      expect(xPackInfo.license.isActive()).to.be(false);
-
-      license$.next(createLicense({ status: 'some other value' }));
-      expect(xPackInfo.license.isActive()).to.be(false);
-
-      license$.next(createLicense({ status: 'active' }));
-      expect(xPackInfo.license.isActive()).to.be(true);
-
-      license$.next(createLicense({ status: undefined, error: 'error-reason' }));
-      expect(xPackInfo.license.isActive()).to.be(false);
-    });
-
-    it('getExpiryDateInMillis() is based on the value returned from the backend.', async () => {
-      expect(xPackInfo.license.getExpiryDateInMillis()).to.be(1286575200000);
-
-      license$.next(createLicense({ expiryDateInMillis: 10203040 }));
-      expect(xPackInfo.license.getExpiryDateInMillis()).to.be(10203040);
-
-      license$.next(createLicense({ expiryDateInMillis: undefined, error: 'error-reason' }));
-      expect(xPackInfo.license.getExpiryDateInMillis()).to.be(undefined);
-    });
-
-    it('getType() is based on the value returned from the backend.', async () => {
-      expect(xPackInfo.license.getType()).to.be('gold');
-
-      license$.next(createLicense({ type: 'basic' }));
-      expect(xPackInfo.license.getType()).to.be('basic');
-
-      license$.next(createLicense({ type: undefined, error: 'error-reason' }));
-      expect(xPackInfo.license.getType()).to.be(undefined);
-    });
-
-    it('isOneOf() correctly determines if current license is presented in the specified list.', async () => {
-      expect(xPackInfo.license.isOneOf('gold')).to.be(true);
-      expect(xPackInfo.license.isOneOf(['gold', 'basic'])).to.be(true);
-      expect(xPackInfo.license.isOneOf(['platinum', 'basic'])).to.be(false);
-      expect(xPackInfo.license.isOneOf('standard')).to.be(false);
-
-      license$.next(createLicense({ mode: 'basic' }));
-
-      expect(xPackInfo.license.isOneOf('basic')).to.be(true);
-      expect(xPackInfo.license.isOneOf(['gold', 'basic'])).to.be(true);
-      expect(xPackInfo.license.isOneOf(['platinum', 'gold'])).to.be(false);
-      expect(xPackInfo.license.isOneOf('standard')).to.be(false);
-    });
-  });
-
-  describe('feature', () => {
-    let xPackInfo;
-    let license$;
-    beforeEach(async () => {
-      license$ = new BehaviorSubject(
-        createLicense(
-          {},
-          {
-            feature: {
-              isAvailable: false,
-              isEnabled: true,
-            },
-          }
-        )
-      );
-      xPackInfo = new XPackInfo(mockServer, {
-        licensing: {
-          license$,
-          refresh: () => null,
-        },
-      });
-    });
-
-    it('isAvailable() checks whether particular feature is available.', async () => {
-      const availableFeatureOne = xPackInfo.feature('security');
-      const availableFeatureTwo = xPackInfo.feature('watcher');
-      const unavailableFeatureOne = xPackInfo.feature('feature');
-      const unavailableFeatureTwo = xPackInfo.feature('non-existing-feature');
-
-      expect(availableFeatureOne.isAvailable()).to.be(true);
-      expect(availableFeatureTwo.isAvailable()).to.be(true);
-      expect(unavailableFeatureOne.isAvailable()).to.be(false);
-      expect(unavailableFeatureTwo.isAvailable()).to.be(false);
-    });
-
-    it('isEnabled() checks whether particular feature is enabled.', async () => {
-      const enabledFeatureOne = xPackInfo.feature('security');
-      const enabledFeatureTwo = xPackInfo.feature('feature');
-      const disabledFeatureOne = xPackInfo.feature('watcher');
-      const disabledFeatureTwo = xPackInfo.feature('non-existing-feature');
-
-      expect(enabledFeatureOne.isEnabled()).to.be(true);
-      expect(enabledFeatureTwo.isEnabled()).to.be(true);
-      expect(disabledFeatureOne.isEnabled()).to.be(false);
-      expect(disabledFeatureTwo.isEnabled()).to.be(false);
-    });
-
-    it('registerLicenseCheckResultsGenerator() allows to fill in XPack Info feature specific info.', async () => {
-      const securityFeature = xPackInfo.feature('security');
-      const watcherFeature = xPackInfo.feature('watcher');
-
-      expect(xPackInfo.toJSON().features.security).to.be(undefined);
-      expect(xPackInfo.toJSON().features.watcher).to.be(undefined);
-
-      securityFeature.registerLicenseCheckResultsGenerator((info) => {
-        return {
-          isXPackInfo: info instanceof XPackInfo,
-          license: info.license.getType(),
-          someCustomValue: 100500,
-        };
-      });
-
-      expect(xPackInfo.toJSON().features.security).to.eql({
-        isXPackInfo: true,
-        license: 'gold',
-        someCustomValue: 100500,
-      });
-      expect(xPackInfo.toJSON().features.watcher).to.be(undefined);
-
-      watcherFeature.registerLicenseCheckResultsGenerator((info) => {
-        return {
-          isXPackInfo: info instanceof XPackInfo,
-          license: info.license.getType(),
-          someAnotherCustomValue: 500100,
-        };
-      });
-
-      expect(xPackInfo.toJSON().features.security).to.eql({
-        isXPackInfo: true,
-        license: 'gold',
-        someCustomValue: 100500,
-      });
-      expect(xPackInfo.toJSON().features.watcher).to.eql({
-        isXPackInfo: true,
-        license: 'gold',
-        someAnotherCustomValue: 500100,
-      });
-
-      license$.next(createLicense({ type: 'platinum' }));
-
-      expect(xPackInfo.toJSON().features.security).to.eql({
-        isXPackInfo: true,
-        license: 'platinum',
-        someCustomValue: 100500,
-      });
-      expect(xPackInfo.toJSON().features.watcher).to.eql({
-        isXPackInfo: true,
-        license: 'platinum',
-        someAnotherCustomValue: 500100,
-      });
-    });
-
-    it('getLicenseCheckResults() correctly returns feature specific info.', async () => {
-      const securityFeature = xPackInfo.feature('security');
-      const watcherFeature = xPackInfo.feature('watcher');
-
-      expect(securityFeature.getLicenseCheckResults()).to.be(undefined);
-      expect(watcherFeature.getLicenseCheckResults()).to.be(undefined);
-
-      securityFeature.registerLicenseCheckResultsGenerator((info) => {
-        return {
-          isXPackInfo: info instanceof XPackInfo,
-          license: info.license.getType(),
-          someCustomValue: 100500,
-        };
-      });
-
-      expect(securityFeature.getLicenseCheckResults()).to.eql({
-        isXPackInfo: true,
-        license: 'gold',
-        someCustomValue: 100500,
-      });
-      expect(watcherFeature.getLicenseCheckResults()).to.be(undefined);
-
-      watcherFeature.registerLicenseCheckResultsGenerator((info) => {
-        return {
-          isXPackInfo: info instanceof XPackInfo,
-          license: info.license.getType(),
-          someAnotherCustomValue: 500100,
-        };
-      });
-
-      expect(securityFeature.getLicenseCheckResults()).to.eql({
-        isXPackInfo: true,
-        license: 'gold',
-        someCustomValue: 100500,
-      });
-      expect(watcherFeature.getLicenseCheckResults()).to.eql({
-        isXPackInfo: true,
-        license: 'gold',
-        someAnotherCustomValue: 500100,
-      });
-
-      license$.next(createLicense({ type: 'platinum' }));
-
-      expect(securityFeature.getLicenseCheckResults()).to.eql({
-        isXPackInfo: true,
-        license: 'platinum',
-        someCustomValue: 100500,
-      });
-      expect(watcherFeature.getLicenseCheckResults()).to.eql({
-        isXPackInfo: true,
-        license: 'platinum',
-        someAnotherCustomValue: 500100,
-      });
-    });
-  });
-
-  it('onLicenseInfoChange() allows to subscribe to license update', async () => {
-    const license$ = new BehaviorSubject(createLicense());
-
-    const xPackInfo = new XPackInfo(mockServer, {
-      licensing: {
-        license$,
-        refresh: () => null,
-      },
-    });
-
-    const watcherFeature = xPackInfo.feature('watcher');
-    watcherFeature.registerLicenseCheckResultsGenerator((info) => ({
-      type: info.license.getType(),
-    }));
-
-    const statuses = [];
-    xPackInfo.onLicenseInfoChange(() => statuses.push(watcherFeature.getLicenseCheckResults()));
-
-    license$.next(createLicense({ type: 'basic' }));
-    expect(statuses).to.eql([{ type: 'basic' }]);
-
-    license$.next(createLicense({ type: 'trial' }));
-    expect(statuses).to.eql([{ type: 'basic' }, { type: 'trial' }]);
-  });
-
-  it('refreshNow() leads to onLicenseInfoChange()', async () => {
-    const license$ = new BehaviorSubject(createLicense());
-
-    const xPackInfo = new XPackInfo(mockServer, {
-      licensing: {
-        license$,
-        refresh: () => license$.next({ type: 'basic' }),
-      },
-    });
-
-    const watcherFeature = xPackInfo.feature('watcher');
-
-    watcherFeature.registerLicenseCheckResultsGenerator((info) => ({
-      type: info.license.getType(),
-    }));
-
-    const statuses = [];
-    xPackInfo.onLicenseInfoChange(() => statuses.push(watcherFeature.getLicenseCheckResults()));
-
-    await xPackInfo.refreshNow();
-    expect(statuses).to.eql([{ type: 'basic' }]);
-  });
-
-  it('getSignature() returns correct signature.', async () => {
-    const license$ = new BehaviorSubject(createLicense());
-    const xPackInfo = new XPackInfo(mockServer, {
-      licensing: {
-        license$,
-        refresh: () => null,
-      },
-    });
-
-    expect(xPackInfo.getSignature()).to.be(
-      getSignature({
-        license: {
-          type: 'gold',
-          isActive: true,
-          expiryDateInMillis: 1286575200000,
-        },
-        features: {},
-      })
-    );
-
-    license$.next(createLicense({ type: 'platinum', expiryDateInMillis: 20304050 }));
-
-    const expectedSignature = getSignature({
-      license: {
-        type: 'platinum',
-        isActive: true,
-        expiryDateInMillis: 20304050,
-      },
-      features: {},
-    });
-    expect(xPackInfo.getSignature()).to.be(expectedSignature);
-
-    // Should stay the same after refresh if nothing changed.
-    license$.next(createLicense({ type: 'platinum', expiryDateInMillis: 20304050 }));
-
-    expect(xPackInfo.getSignature()).to.be(expectedSignature);
-  });
-});
diff --git a/x-pack/legacy/plugins/xpack_main/server/lib/setup_xpack_main.js b/x-pack/legacy/plugins/xpack_main/server/lib/setup_xpack_main.js
deleted file mode 100644
index fd4e3c86d0ca7..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/lib/setup_xpack_main.js
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { pairwise } from 'rxjs/operators';
-import { XPackInfo } from './xpack_info';
-
-/**
- * Setup the X-Pack Main plugin. This is fired every time that the Elasticsearch plugin becomes Green.
- *
- * This will ensure that X-Pack is installed on the Elasticsearch cluster, as well as trigger the initial
- * polling for _xpack/info.
- *
- * @param server {Object} The Kibana server object.
- */
-export function setupXPackMain(server) {
-  const info = new XPackInfo(server, { licensing: server.newPlatform.setup.plugins.licensing });
-
-  server.expose('info', info);
-
-  // trigger an xpack info refresh whenever the elasticsearch plugin status changes
-  server.newPlatform.setup.core.status.core$
-    .pipe(pairwise())
-    .subscribe(async ([coreLast, coreCurrent]) => {
-      if (coreLast.elasticsearch.level !== coreCurrent.elasticsearch.level) {
-        await info.refreshNow();
-      }
-    });
-
-  return info;
-}
diff --git a/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info.ts b/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info.ts
deleted file mode 100644
index aa66532a2897d..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info.ts
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { createHash } from 'crypto';
-import { Legacy } from 'kibana';
-
-import { XPackInfoLicense } from './xpack_info_license';
-
-import { LicensingPluginSetup, ILicense } from '../../../../../plugins/licensing/server';
-
-export interface XPackInfoOptions {
-  clusterSource?: string;
-  pollFrequencyInMillis: number;
-}
-
-type LicenseGeneratorCheck = (xpackInfo: XPackInfo) => any;
-
-export interface XPackFeature {
-  isAvailable(): boolean;
-  isEnabled(): boolean;
-  registerLicenseCheckResultsGenerator(generator: LicenseGeneratorCheck): void;
-  getLicenseCheckResults(): any;
-}
-
-interface Deps {
-  licensing: LicensingPluginSetup;
-}
-
-/**
- * A helper that provides a convenient way to access XPack Info returned by Elasticsearch.
- */
-export class XPackInfo {
-  /**
-   * XPack License object.
-   * @type {XPackInfoLicense}
-   * @private
-   */
-  _license: XPackInfoLicense;
-
-  /**
-   * Feature name <-> feature license check generator function mapping.
-   * @type {Map<string, Function>}
-   * @private
-   */
-  _featureLicenseCheckResultsGenerators = new Map<string, LicenseGeneratorCheck>();
-
-  /**
-   * Set of listener functions that will be called whenever the license
-   * info changes
-   * @type {Set<Function>}
-   */
-  _licenseInfoChangedListeners = new Set<() => void>();
-
-  /**
-   * Cache that may contain last xpack info API response or error, json representation
-   * of xpack info and xpack info signature.
-   * @type {{response: Object|undefined, error: Object|undefined, json: Object|undefined, signature: string|undefined}}
-   * @private
-   */
-  private _cache: {
-    license?: ILicense;
-    error?: string;
-    json?: Record<string, any>;
-    signature?: string;
-  };
-
-  /**
-   * XPack License instance.
-   * @returns {XPackInfoLicense}
-   */
-  public get license() {
-    return this._license;
-  }
-
-  private readonly licensingPlugin: LicensingPluginSetup;
-
-  /**
-   * Constructs XPack info object.
-   * @param {Hapi.Server} server HapiJS server instance.
-   */
-  constructor(server: Legacy.Server, deps: Deps) {
-    if (!deps.licensing) {
-      throw new Error('XPackInfo requires enabled Licensing plugin');
-    }
-    this.licensingPlugin = deps.licensing;
-
-    this._cache = {};
-
-    this.licensingPlugin.license$.subscribe((license: ILicense) => {
-      if (license.isActive) {
-        this._cache = {
-          license,
-          error: undefined,
-        };
-      } else {
-        this._cache = {
-          license,
-          error: license.error,
-        };
-      }
-
-      this._licenseInfoChangedListeners.forEach((fn) => fn());
-    });
-
-    this._license = new XPackInfoLicense(() => this._cache.license);
-  }
-
-  /**
-   * Checks whether XPack info is available.
-   * @returns {boolean}
-   */
-  isAvailable() {
-    return Boolean(this._cache.license?.isAvailable);
-  }
-
-  /**
-   * Checks whether ES was available
-   * @returns {boolean}
-   */
-  isXpackUnavailable() {
-    return (
-      this._cache.error &&
-      this._cache.error === 'X-Pack plugin is not installed on the Elasticsearch cluster.'
-    );
-  }
-
-  /**
-   * If present, describes the reason why XPack info is not available.
-   * @returns {Error|string}
-   */
-  unavailableReason() {
-    return this._cache.license?.getUnavailableReason();
-  }
-
-  onLicenseInfoChange(handler: () => void) {
-    this._licenseInfoChangedListeners.add(handler);
-  }
-
-  /**
-   * Queries server to get the updated XPack info.
-   * @returns {Promise.<XPackInfo>}
-   */
-  async refreshNow() {
-    await this.licensingPlugin.refresh();
-    return this;
-  }
-
-  /**
-   * Returns a wrapper around XPack info that gives an access to the properties of
-   * the specific feature.
-   * @param {string} name Name of the feature to get a wrapper for.
-   * @returns {Object}
-   */
-  feature(name: string): XPackFeature {
-    return {
-      /**
-       * Checks whether feature is available (permitted by the current license).
-       * @returns {boolean}
-       */
-      isAvailable: () => {
-        return Boolean(this._cache.license?.getFeature(name).isAvailable);
-      },
-
-      /**
-       * Checks whether feature is enabled (not disabled by the configuration specifically).
-       * @returns {boolean}
-       */
-      isEnabled: () => {
-        return Boolean(this._cache.license?.getFeature(name).isEnabled);
-      },
-
-      /**
-       * Registers a `generator` function that will be called with XPackInfo instance as
-       * argument whenever XPack info changes. Whatever `generator` returns will be stored
-       * in XPackInfo JSON representation and can be accessed with `getLicenseCheckResults`.
-       * @param {Function} generator Function to call whenever XPackInfo changes.
-       */
-      registerLicenseCheckResultsGenerator: (generator: LicenseGeneratorCheck) => {
-        this._featureLicenseCheckResultsGenerators.set(name, generator);
-
-        // Since JSON representation and signature are cached we should invalidate them to
-        // include results from newly registered generator when they are requested.
-        this._cache.json = undefined;
-        this._cache.signature = undefined;
-      },
-
-      /**
-       * Returns license check results that were previously produced by the `generator` function.
-       * @returns {Object}
-       */
-      getLicenseCheckResults: () => this.toJSON().features[name],
-    };
-  }
-
-  /**
-   * Extracts string md5 hash from the stringified version of license JSON representation.
-   * @returns {string}
-   */
-  getSignature() {
-    if (this._cache.signature) {
-      return this._cache.signature;
-    }
-
-    this._cache.signature = createHash('md5').update(JSON.stringify(this.toJSON())).digest('hex');
-
-    return this._cache.signature;
-  }
-
-  /**
-   * Returns JSON representation of the license object that is suitable for serialization.
-   * @returns {Object}
-   */
-  toJSON() {
-    if (this._cache.json) {
-      return this._cache.json;
-    }
-
-    this._cache.json = {
-      license: {
-        type: this.license.getType(),
-        isActive: this.license.isActive(),
-        expiryDateInMillis: this.license.getExpiryDateInMillis(),
-      },
-      features: {},
-    };
-
-    // Set response elements specific to each feature. To do this,
-    // call the license check results generator for each feature, passing them
-    // the xpack info object
-    for (const [feature, licenseChecker] of this._featureLicenseCheckResultsGenerators) {
-      // return value expected to be a dictionary object.
-      this._cache.json.features[feature] = licenseChecker(this);
-    }
-
-    return this._cache.json;
-  }
-}
diff --git a/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info_license.test.js b/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info_license.test.js
deleted file mode 100644
index ccb5742216ca7..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info_license.test.js
+++ /dev/null
@@ -1,207 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { licensingMock } from '../../../../../plugins/licensing/server/mocks';
-import { XPackInfoLicense } from './xpack_info_license';
-
-function getXPackInfoLicense(getRawLicense) {
-  return new XPackInfoLicense(getRawLicense);
-}
-
-describe('XPackInfoLicense', () => {
-  const xpackInfoLicenseUndefined = getXPackInfoLicense(() => {});
-  let xpackInfoLicense;
-  let getRawLicense;
-
-  beforeEach(() => {
-    getRawLicense = jest.fn();
-    xpackInfoLicense = getXPackInfoLicense(getRawLicense);
-  });
-
-  test('getUid returns uid field', () => {
-    const uid = 'abc123';
-
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { uid } }));
-
-    expect(xpackInfoLicense.getUid()).toBe(uid);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    expect(xpackInfoLicenseUndefined.getUid()).toBe(undefined);
-  });
-
-  test('isActive returns true if status is active', () => {
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { status: 'active' } }));
-
-    expect(xpackInfoLicense.isActive()).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-  });
-
-  test('isActive returns false if status is not active', () => {
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { status: 'aCtIvE' } })); // needs to match exactly
-
-    expect(xpackInfoLicense.isActive()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    expect(xpackInfoLicenseUndefined.isActive()).toBe(false);
-  });
-
-  test('getExpiryDateInMillis returns expiry_date_in_millis', () => {
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { expiryDateInMillis: 123 } })
-    );
-
-    expect(xpackInfoLicense.getExpiryDateInMillis()).toBe(123);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    expect(xpackInfoLicenseUndefined.getExpiryDateInMillis()).toBe(undefined);
-  });
-
-  test('isOneOf returns true of the mode includes one of the types', () => {
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { mode: 'platinum' } }));
-
-    expect(xpackInfoLicense.isOneOf('platinum')).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    expect(xpackInfoLicense.isOneOf(['platinum'])).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(2);
-    expect(xpackInfoLicense.isOneOf(['gold', 'platinum'])).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(3);
-    expect(xpackInfoLicense.isOneOf(['platinum', 'gold'])).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(4);
-    expect(xpackInfoLicense.isOneOf(['basic', 'gold'])).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(5);
-    expect(xpackInfoLicense.isOneOf(['basic'])).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(6);
-
-    expect(xpackInfoLicenseUndefined.isOneOf(['platinum', 'gold'])).toBe(false);
-  });
-
-  test('getType returns the type', () => {
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { type: 'basic' } }));
-
-    expect(xpackInfoLicense.getType()).toBe('basic');
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { type: 'gold' } }));
-
-    expect(xpackInfoLicense.getType()).toBe('gold');
-    expect(getRawLicense).toHaveBeenCalledTimes(2);
-
-    expect(xpackInfoLicenseUndefined.getType()).toBe(undefined);
-  });
-
-  test('getMode returns the mode', () => {
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { mode: 'basic' } }));
-
-    expect(xpackInfoLicense.getMode()).toBe('basic');
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    getRawLicense.mockReturnValue(licensingMock.createLicense({ license: { mode: 'gold' } }));
-
-    expect(xpackInfoLicense.getMode()).toBe('gold');
-    expect(getRawLicense).toHaveBeenCalledTimes(2);
-
-    expect(xpackInfoLicenseUndefined.getMode()).toBe(undefined);
-  });
-
-  test('isActiveLicense returns the true if active and typeChecker matches', () => {
-    const expectAbc123 = (type) => type === 'abc123';
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'active', mode: 'abc123' } })
-    );
-
-    expect(xpackInfoLicense.isActiveLicense(expectAbc123)).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'NOTactive', mode: 'abc123' } })
-    );
-
-    expect(xpackInfoLicense.isActiveLicense(expectAbc123)).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(2);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'NOTactive', mode: 'NOTabc123' } })
-    );
-
-    expect(xpackInfoLicense.isActiveLicense(expectAbc123)).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(3);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'active', mode: 'NOTabc123' } })
-    );
-
-    expect(xpackInfoLicense.isActiveLicense(expectAbc123)).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(4);
-
-    expect(xpackInfoLicenseUndefined.isActive(expectAbc123)).toBe(false);
-  });
-
-  test('isBasic returns the true if active and basic', () => {
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'active', mode: 'basic' } })
-    );
-
-    expect(xpackInfoLicense.isBasic()).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'NOTactive', mode: 'gold' } })
-    );
-
-    expect(xpackInfoLicense.isBasic()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(2);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'NOTactive', mode: 'trial' } })
-    );
-
-    expect(xpackInfoLicense.isBasic()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(3);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'active', mode: 'platinum' } })
-    );
-
-    expect(xpackInfoLicense.isBasic()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(4);
-
-    expect(xpackInfoLicenseUndefined.isBasic()).toBe(false);
-  });
-
-  test('isNotBasic returns the true if active and not basic', () => {
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'active', mode: 'platinum' } })
-    );
-
-    expect(xpackInfoLicense.isNotBasic()).toBe(true);
-    expect(getRawLicense).toHaveBeenCalledTimes(1);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'NOTactive', mode: 'gold' } })
-    );
-
-    expect(xpackInfoLicense.isNotBasic()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(2);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'NOTactive', mode: 'trial' } })
-    );
-
-    expect(xpackInfoLicense.isNotBasic()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(3);
-
-    getRawLicense.mockReturnValue(
-      licensingMock.createLicense({ license: { status: 'active', mode: 'basic' } })
-    );
-
-    expect(xpackInfoLicense.isNotBasic()).toBe(false);
-    expect(getRawLicense).toHaveBeenCalledTimes(4);
-
-    expect(xpackInfoLicenseUndefined.isNotBasic()).toBe(false);
-  });
-});
diff --git a/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info_license.ts b/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info_license.ts
deleted file mode 100644
index dd53f63909475..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/lib/xpack_info_license.ts
+++ /dev/null
@@ -1,111 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { ILicense } from '../../../../../plugins/licensing/server';
-
-/**
- * "View" for XPack Info license information.
- */
-export class XPackInfoLicense {
-  /**
-   * Function that retrieves license information from the XPack info object.
-   * @type {Function}
-   * @private
-   */
-  _getRawLicense: () => ILicense | undefined;
-
-  constructor(getRawLicense: () => ILicense | undefined) {
-    this._getRawLicense = getRawLicense;
-  }
-
-  /**
-   * Returns unique identifier of the license.
-   * @returns {string|undefined}
-   */
-  getUid() {
-    return this._getRawLicense()?.uid;
-  }
-
-  /**
-   * Indicates whether license is still active.
-   * @returns {boolean}
-   */
-  isActive() {
-    return Boolean(this._getRawLicense()?.isActive);
-  }
-
-  /**
-   * Returns license expiration date in ms.
-   *
-   * Note: A basic license created after 6.3 will have no expiration, thus returning undefined.
-   *
-   * @returns {number|undefined}
-   */
-  getExpiryDateInMillis() {
-    return this._getRawLicense()?.expiryDateInMillis;
-  }
-
-  /**
-   * Checks if the license is represented in a specified license list.
-   * @param {String} candidateLicenses List of the licenses to check against.
-   * @returns {boolean}
-   */
-  isOneOf(candidateLicenses: string | string[]) {
-    const candidates = Array.isArray(candidateLicenses) ? candidateLicenses : [candidateLicenses];
-    const mode = this._getRawLicense()?.mode;
-    return Boolean(mode && candidates.includes(mode));
-  }
-
-  /**
-   * Returns type of the license (basic, gold etc.).
-   * @returns {string|undefined}
-   */
-  getType() {
-    return this._getRawLicense()?.type;
-  }
-
-  /**
-   * Returns mode of the license (basic, gold etc.). This is the "effective" type of the license.
-   * @returns {string|undefined}
-   */
-  getMode() {
-    return this._getRawLicense()?.mode;
-  }
-
-  /**
-   * Determine if the current license is active and the supplied {@code type}.
-   *
-   * @param {Function} typeChecker The license type checker.
-   * @returns {boolean}
-   */
-  isActiveLicense(typeChecker: (mode: string) => boolean) {
-    const license = this._getRawLicense();
-
-    return Boolean(license?.isActive && typeChecker(license.mode as any));
-  }
-
-  /**
-   * Determine if the license is an active, basic license.
-   *
-   * Note: This also verifies that the license is active. Therefore it is not safe to assume that !isBasic() === isNotBasic().
-   *
-   * @returns {boolean}
-   */
-  isBasic() {
-    return this.isActiveLicense((mode) => mode === 'basic');
-  }
-
-  /**
-   * Determine if the license is an active, non-basic license (e.g., standard, gold, platinum, or trial).
-   *
-   * Note: This also verifies that the license is active. Therefore it is not safe to assume that !isBasic() === isNotBasic().
-   *
-   * @returns {boolean}
-   */
-  isNotBasic() {
-    return this.isActiveLicense((mode) => mode !== 'basic');
-  }
-}
diff --git a/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/__tests__/xpack_info.js b/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/__tests__/xpack_info.js
deleted file mode 100644
index 540d9f63ea6c8..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/__tests__/xpack_info.js
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import sinon from 'sinon';
-
-import { xpackInfoRoute } from '../xpack_info';
-
-describe('XPackInfo routes', () => {
-  let serverStub;
-  beforeEach(() => {
-    serverStub = {
-      route: sinon.stub(),
-      plugins: {
-        xpack_main: {
-          info: sinon.stub({ isAvailable() {}, toJSON() {} }),
-        },
-      },
-    };
-
-    xpackInfoRoute(serverStub);
-  });
-
-  it('correctly initialize XPack Info route.', () => {
-    sinon.assert.calledWithExactly(serverStub.route, {
-      method: 'GET',
-      path: '/api/xpack/v1/info',
-      handler: sinon.match.func,
-    });
-  });
-
-  it('replies with `Not Found` Boom error if `xpackInfo` is not available.', () => {
-    serverStub.plugins.xpack_main.info.isAvailable.returns(false);
-
-    const onRouteHandler = serverStub.route.firstCall.args[0].handler;
-    const response = onRouteHandler();
-
-    expect(response.isBoom).to.be(true);
-    expect(response.message).to.be('Not Found');
-    expect(response.output.statusCode).to.be(404);
-  });
-
-  it('replies with pre-processed `xpackInfo` if it is available.', () => {
-    serverStub.plugins.xpack_main.info.isAvailable.returns(true);
-    serverStub.plugins.xpack_main.info.toJSON.returns({
-      license: {
-        type: 'gold',
-        isActive: true,
-        expiryDateInMillis: 1509368280381,
-      },
-      features: {
-        security: {
-          showLogin: true,
-          allowLogin: true,
-          showLinks: false,
-          allowRoleDocumentLevelSecurity: false,
-          allowRoleFieldLevelSecurity: false,
-        },
-      },
-    });
-
-    const onRouteHandler = serverStub.route.firstCall.args[0].handler;
-    const response = onRouteHandler();
-
-    expect(response).to.eql({
-      license: {
-        type: 'gold',
-        is_active: true,
-        expiry_date_in_millis: 1509368280381,
-      },
-      features: {
-        security: {
-          show_login: true,
-          allow_login: true,
-          show_links: false,
-          allow_role_document_level_security: false,
-          allow_role_field_level_security: false,
-        },
-      },
-    });
-  });
-});
diff --git a/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/xpack_info.js b/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/xpack_info.js
deleted file mode 100644
index 3cc57ae9fcab4..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/xpack_info.js
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import Boom from 'boom';
-import { convertKeysToSnakeCaseDeep } from '../../../../../../server/lib/key_case_converter';
-
-/*
- * A route to provide the basic XPack info for the production cluster
- */
-export function xpackInfoRoute(server) {
-  server.route({
-    method: 'GET',
-    path: '/api/xpack/v1/info',
-    handler() {
-      const xPackInfo = server.plugins.xpack_main.info;
-
-      return xPackInfo.isAvailable()
-        ? convertKeysToSnakeCaseDeep(xPackInfo.toJSON())
-        : Boom.notFound();
-    },
-  });
-}
diff --git a/x-pack/legacy/plugins/xpack_main/server/xpack_main.d.ts b/x-pack/legacy/plugins/xpack_main/server/xpack_main.d.ts
deleted file mode 100644
index c2ec5662ad12e..0000000000000
--- a/x-pack/legacy/plugins/xpack_main/server/xpack_main.d.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import KbnServer from 'src/legacy/server/kbn_server';
-import { KibanaFeature } from '../../../../plugins/features/server';
-import { XPackInfo, XPackInfoOptions } from './lib/xpack_info';
-export { XPackFeature } from './lib/xpack_info';
-
-export interface XPackMainPlugin {
-  info: XPackInfo;
-}
diff --git a/x-pack/legacy/server/lib/__tests__/key_case_converter.js b/x-pack/legacy/server/lib/__tests__/key_case_converter.js
deleted file mode 100644
index 7ed9fa668ae66..0000000000000
--- a/x-pack/legacy/server/lib/__tests__/key_case_converter.js
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { convertKeysToSnakeCaseDeep, convertKeysToCamelCaseDeep } from '../key_case_converter';
-
-describe('key_case_converter', () => {
-  let testObject;
-
-  beforeEach(() => {
-    testObject = {
-      topLevelKey1: {
-        innerLevelKey1: 17,
-        inner_level_key2: [19, 31],
-      },
-      top_level_key2: {
-        innerLevelKey1: 'foo_fooFoo',
-        inner_level_key2: [{ foo_bar: 29 }, { barBar: 37 }],
-      },
-    };
-  });
-
-  describe('convertKeysToSnakeCaseDeep', () => {
-    it('should recursively convert camelCase keys to snake_case keys', () => {
-      const expectedResultObject = {
-        top_level_key_1: {
-          inner_level_key_1: 17,
-          inner_level_key_2: [19, 31],
-        },
-        top_level_key_2: {
-          inner_level_key_1: 'foo_fooFoo',
-          inner_level_key_2: [{ foo_bar: 29 }, { bar_bar: 37 }],
-        },
-      };
-      expect(convertKeysToSnakeCaseDeep(testObject)).to.eql(expectedResultObject);
-    });
-
-    it('should not modify original object', () => {
-      convertKeysToSnakeCaseDeep(testObject);
-      expect(Object.keys(testObject)).to.contain('topLevelKey1');
-      expect(Object.keys(testObject.topLevelKey1)).to.contain('innerLevelKey1');
-    });
-
-    it('should preserve inner arrays', () => {
-      const result = convertKeysToSnakeCaseDeep(testObject);
-      expect(testObject.topLevelKey1.inner_level_key2).to.be.an(Array);
-      expect(result.top_level_key_1.inner_level_key_2).to.be.an(Array);
-    });
-
-    it('should preserve top-level arrays', () => {
-      testObject = [{ foo_bar: 17 }, [19, { barBaz: 'qux' }]];
-      const expectedResultObject = [{ foo_bar: 17 }, [19, { bar_baz: 'qux' }]];
-      const result = convertKeysToSnakeCaseDeep(testObject);
-      expect(testObject).to.be.an(Array);
-      expect(testObject[1]).to.be.an(Array);
-      expect(result).to.be.an(Array);
-      expect(result[1]).to.be.an(Array);
-      expect(result).to.eql(expectedResultObject);
-    });
-
-    it('should throw an error if something other an object or array is passed in', () => {
-      const expectedErrorMessageRegexp = /Specified object should be an Object or Array/;
-      expect(convertKeysToSnakeCaseDeep)
-        .withArgs('neither an object nor an array')
-        .to.throwException(expectedErrorMessageRegexp);
-    });
-  });
-
-  describe('convertKeysToCamelCaseDeep', () => {
-    it('should recursively convert snake_case keys to camelCase keys', () => {
-      const expectedResultObject = {
-        topLevelKey1: {
-          innerLevelKey1: 17,
-          innerLevelKey2: [19, 31],
-        },
-        topLevelKey2: {
-          innerLevelKey1: 'foo_fooFoo',
-          innerLevelKey2: [{ fooBar: 29 }, { barBar: 37 }],
-        },
-      };
-      expect(convertKeysToCamelCaseDeep(testObject)).to.eql(expectedResultObject);
-    });
-
-    it('should not modify original object', () => {
-      convertKeysToCamelCaseDeep(testObject);
-      expect(Object.keys(testObject)).to.contain('top_level_key2');
-      expect(Object.keys(testObject.topLevelKey1)).to.contain('inner_level_key2');
-    });
-
-    it('should preserve inner arrays', () => {
-      const result = convertKeysToCamelCaseDeep(testObject);
-      expect(testObject.topLevelKey1.inner_level_key2).to.be.an(Array);
-      expect(result.topLevelKey1.innerLevelKey2).to.be.an(Array);
-    });
-
-    it('should preserve top-level arrays', () => {
-      testObject = [{ foo_bar: 17 }, [19, { barBaz: 'qux' }]];
-      const expectedResultObject = [{ fooBar: 17 }, [19, { barBaz: 'qux' }]];
-      const result = convertKeysToCamelCaseDeep(testObject);
-      expect(testObject).to.be.an(Array);
-      expect(testObject[1]).to.be.an(Array);
-      expect(result).to.be.an(Array);
-      expect(result[1]).to.be.an(Array);
-      expect(result).to.eql(expectedResultObject);
-    });
-
-    it('should throw an error if something other an object or array is passed in', () => {
-      const expectedErrorMessageRegexp = /Specified object should be an Object or Array/;
-      expect(convertKeysToCamelCaseDeep)
-        .withArgs('neither an object nor an array')
-        .to.throwException(expectedErrorMessageRegexp);
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/__tests__/kibana_state.js b/x-pack/legacy/server/lib/__tests__/kibana_state.js
deleted file mode 100644
index d1b4142b10446..0000000000000
--- a/x-pack/legacy/server/lib/__tests__/kibana_state.js
+++ /dev/null
@@ -1,129 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import rison from 'rison-node';
-import { parseKibanaState } from '../parse_kibana_state';
-
-const stateIndices = {
-  global: '_g',
-  app: '_a',
-};
-const globalTime =
-  '(refreshInterval:(display:Off,pause:!f,value:0),time:(from:now-15m,mode:quick,to:now))';
-
-describe('Kibana state', function () {
-  describe('type checking', function () {
-    it('should throw if not given an object', function () {
-      const fn = () => parseKibanaState('i am not an object', 'global');
-      const fn2 = () => parseKibanaState(['arrays are not valid either'], 'global');
-      expect(fn).to.throwException(/must be an object/i);
-      expect(fn2).to.throwException(/must be an object/i);
-    });
-
-    it('should throw with invalid type', function () {
-      const fn = () => parseKibanaState({}, 'this is an invalid state type');
-      expect(fn).to.throwException(/unknown state type/i);
-    });
-  });
-
-  describe('value of exists', function () {
-    it('should be false if state does not exist', function () {
-      const state = parseKibanaState({}, 'global');
-      expect(state.exists).to.equal(false);
-    });
-
-    it('should be true if state exists', function () {
-      const query = {};
-      query[stateIndices.global] = rison.encode({ hello: 'world' });
-      const state = parseKibanaState(query, 'global');
-      expect(state.exists).to.equal(true);
-    });
-  });
-
-  describe('instance methods', function () {
-    let query;
-
-    beforeEach(function () {
-      query = {};
-      query[stateIndices.global] = globalTime;
-    });
-
-    describe('get', function () {
-      it('should return the value', function () {
-        const state = parseKibanaState(query, 'global');
-        const { refreshInterval } = rison.decode(globalTime);
-        expect(state.get('refreshInterval')).to.eql(refreshInterval);
-      });
-
-      it('should use the default value for missing props', function () {
-        const defaultValue = 'default value';
-        const state = parseKibanaState(query, 'global');
-        expect(state.get('no such value', defaultValue)).to.equal(defaultValue);
-      });
-    });
-
-    describe('set', function () {
-      it('should update the value of the state', function () {
-        const state = parseKibanaState(query, 'global');
-        expect(state.get('refreshInterval.pause')).to.equal(false);
-
-        state.set(['refreshInterval', 'pause'], true);
-        expect(state.get('refreshInterval.pause')).to.equal(true);
-      });
-
-      it('should create new properties', function () {
-        const prop = 'newProp';
-        const value = 12345;
-        const state = parseKibanaState(query, 'global');
-        expect(state.get(prop)).to.be(undefined);
-
-        state.set(prop, value);
-        expect(state.get(prop)).to.not.be(undefined);
-        expect(state.get(prop)).to.equal(value);
-      });
-    });
-
-    describe('removing properties', function () {
-      it('should remove a single value', function () {
-        const state = parseKibanaState(query, 'global');
-        expect(state.get('refreshInterval')).to.be.an('object');
-
-        state.removeProps('refreshInterval');
-        expect(state.get('refreshInterval')).to.be(undefined);
-      });
-
-      it('should remove multiple values', function () {
-        const state = parseKibanaState(query, 'global');
-        expect(state.get('refreshInterval')).to.be.an('object');
-        expect(state.get('time')).to.be.an('object');
-
-        state.removeProps(['refreshInterval', 'time']);
-        expect(state.get('refreshInterval')).to.be(undefined);
-        expect(state.get('time')).to.be(undefined);
-      });
-    });
-
-    describe('toString', function () {
-      it('should rison encode the state', function () {
-        const state = parseKibanaState(query, 'global');
-        expect(state.toString()).to.equal(globalTime);
-      });
-    });
-
-    describe('toQuery', function () {
-      it('should return an object', function () {
-        const state = parseKibanaState(query, 'global');
-        expect(state.toQuery()).to.be.an('object');
-      });
-
-      it('should contain the kibana state property', function () {
-        const state = parseKibanaState(query, 'global');
-        expect(state.toQuery()).to.have.property(stateIndices.global, globalTime);
-      });
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/check_license/check_license.js b/x-pack/legacy/server/lib/check_license/check_license.js
deleted file mode 100644
index 7695755622310..0000000000000
--- a/x-pack/legacy/server/lib/check_license/check_license.js
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { i18n } from '@kbn/i18n';
-import {
-  LICENSE_STATUS_UNAVAILABLE,
-  LICENSE_STATUS_INVALID,
-  LICENSE_STATUS_EXPIRED,
-  LICENSE_STATUS_VALID,
-  RANKED_LICENSE_TYPES,
-} from '../../../common/constants';
-
-export function checkLicense(pluginName, minimumLicenseRequired, xpackLicenseInfo) {
-  if (!minimumLicenseRequired) {
-    throw new Error(
-      `Error checking license for plugin "${pluginName}". The minimum license required has not been provided.`
-    );
-  }
-
-  if (!RANKED_LICENSE_TYPES.includes(minimumLicenseRequired)) {
-    throw new Error(`Invalid license type supplied to checkLicense: ${minimumLicenseRequired}`);
-  }
-
-  // If, for some reason, we cannot get the license information
-  // from Elasticsearch, assume worst case and disable
-  if (!xpackLicenseInfo || !xpackLicenseInfo.isAvailable()) {
-    return {
-      status: LICENSE_STATUS_UNAVAILABLE,
-      message: i18n.translate('xpack.server.checkLicense.errorUnavailableMessage', {
-        defaultMessage:
-          'You cannot use {pluginName} because license information is not available at this time.',
-        values: { pluginName },
-      }),
-    };
-  }
-
-  const { license } = xpackLicenseInfo;
-  const isLicenseModeValid = license.isOneOf(
-    [...RANKED_LICENSE_TYPES].splice(RANKED_LICENSE_TYPES.indexOf(minimumLicenseRequired))
-  );
-  const isLicenseActive = license.isActive();
-  const licenseType = license.getType();
-
-  // License is not valid
-  if (!isLicenseModeValid) {
-    return {
-      status: LICENSE_STATUS_INVALID,
-      message: i18n.translate('xpack.server.checkLicense.errorUnsupportedMessage', {
-        defaultMessage:
-          'Your {licenseType} license does not support {pluginName}. Please upgrade your license.',
-        values: { licenseType, pluginName },
-      }),
-    };
-  }
-
-  // License is valid but not active
-  if (!isLicenseActive) {
-    return {
-      status: LICENSE_STATUS_EXPIRED,
-      message: i18n.translate('xpack.server.checkLicense.errorExpiredMessage', {
-        defaultMessage:
-          'You cannot use {pluginName} because your {licenseType} license has expired.',
-        values: { licenseType, pluginName },
-      }),
-    };
-  }
-
-  // License is valid and active
-  return {
-    status: LICENSE_STATUS_VALID,
-  };
-}
diff --git a/x-pack/legacy/server/lib/check_license/check_license.test.js b/x-pack/legacy/server/lib/check_license/check_license.test.js
deleted file mode 100644
index 65b599ed4a5f6..0000000000000
--- a/x-pack/legacy/server/lib/check_license/check_license.test.js
+++ /dev/null
@@ -1,132 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { set } from '@elastic/safer-lodash-set';
-import { checkLicense } from './check_license';
-import {
-  LICENSE_STATUS_UNAVAILABLE,
-  LICENSE_STATUS_EXPIRED,
-  LICENSE_STATUS_VALID,
-  LICENSE_TYPE_BASIC,
-} from '../../../common/constants';
-
-describe('check_license', function () {
-  const pluginName = 'Foo';
-  const minimumLicenseRequired = LICENSE_TYPE_BASIC;
-  let mockLicenseInfo;
-  beforeEach(() => (mockLicenseInfo = {}));
-
-  describe('license information is undefined', () => {
-    beforeEach(() => (mockLicenseInfo = undefined));
-
-    it('should set status to unavailable', () => {
-      expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).status).toBe(
-        LICENSE_STATUS_UNAVAILABLE
-      );
-    });
-
-    it('should set a message', () => {
-      expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).message).not.toBe(
-        undefined
-      );
-    });
-  });
-
-  describe('license information is not available', () => {
-    beforeEach(() => (mockLicenseInfo.isAvailable = () => false));
-
-    it('should set status to unavailable', () => {
-      expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).status).toBe(
-        LICENSE_STATUS_UNAVAILABLE
-      );
-    });
-
-    it('should set a message', () => {
-      expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).message).not.toBe(
-        undefined
-      );
-    });
-  });
-
-  describe('license information is available', () => {
-    beforeEach(() => {
-      mockLicenseInfo.isAvailable = () => true;
-      set(mockLicenseInfo, 'license.getType', () => LICENSE_TYPE_BASIC);
-    });
-
-    describe('& license is trial, standard, gold, platinum', () => {
-      beforeEach(() => set(mockLicenseInfo, 'license.isOneOf', () => true));
-
-      describe('& license is active', () => {
-        beforeEach(() => set(mockLicenseInfo, 'license.isActive', () => true));
-
-        it('should set status to valid', () => {
-          expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).status).toBe(
-            LICENSE_STATUS_VALID
-          );
-        });
-
-        it('should not set a message', () => {
-          expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).message).toBe(
-            undefined
-          );
-        });
-      });
-
-      describe('& license is expired', () => {
-        beforeEach(() => set(mockLicenseInfo, 'license.isActive', () => false));
-
-        it('should set status to inactive', () => {
-          expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).status).toBe(
-            LICENSE_STATUS_EXPIRED
-          );
-        });
-
-        it('should set a message', () => {
-          expect(
-            checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).message
-          ).not.toBe(undefined);
-        });
-      });
-    });
-
-    describe('& license is basic', () => {
-      beforeEach(() => set(mockLicenseInfo, 'license.isOneOf', () => true));
-
-      describe('& license is active', () => {
-        beforeEach(() => set(mockLicenseInfo, 'license.isActive', () => true));
-
-        it('should set status to valid', () => {
-          expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).status).toBe(
-            LICENSE_STATUS_VALID
-          );
-        });
-
-        it('should not set a message', () => {
-          expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).message).toBe(
-            undefined
-          );
-        });
-      });
-
-      describe('& license is expired', () => {
-        beforeEach(() => set(mockLicenseInfo, 'license.isActive', () => false));
-
-        it('should set status to inactive', () => {
-          expect(checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).status).toBe(
-            LICENSE_STATUS_EXPIRED
-          );
-        });
-
-        it('should set a message', () => {
-          expect(
-            checkLicense(pluginName, minimumLicenseRequired, mockLicenseInfo).message
-          ).not.toBe(undefined);
-        });
-      });
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/check_license/index.js b/x-pack/legacy/server/lib/check_license/index.js
deleted file mode 100644
index f2c070fd44b6e..0000000000000
--- a/x-pack/legacy/server/lib/check_license/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { checkLicense } from './check_license';
diff --git a/x-pack/legacy/server/lib/constants/admin.ts b/x-pack/legacy/server/lib/constants/admin.ts
deleted file mode 100644
index ab45fdad78e4d..0000000000000
--- a/x-pack/legacy/server/lib/constants/admin.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export const XPACK_DEFAULT_ADMIN_EMAIL_UI_SETTING = 'xPack:defaultAdminEmail';
diff --git a/x-pack/legacy/server/lib/constants/index.ts b/x-pack/legacy/server/lib/constants/index.ts
deleted file mode 100644
index c6cf975fe32f3..0000000000000
--- a/x-pack/legacy/server/lib/constants/index.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { XPACK_DEFAULT_ADMIN_EMAIL_UI_SETTING } from './admin';
-export { XPACK_INFO_API_DEFAULT_POLL_FREQUENCY_IN_MILLIS } from './xpack_info';
diff --git a/x-pack/legacy/server/lib/constants/xpack_info.ts b/x-pack/legacy/server/lib/constants/xpack_info.ts
deleted file mode 100644
index c58bb275245b6..0000000000000
--- a/x-pack/legacy/server/lib/constants/xpack_info.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export const XPACK_INFO_API_DEFAULT_POLL_FREQUENCY_IN_MILLIS = 30001; // 30 seconds
diff --git a/x-pack/legacy/server/lib/create_router/call_with_request_factory/call_with_request_factory.js b/x-pack/legacy/server/lib/create_router/call_with_request_factory/call_with_request_factory.js
deleted file mode 100644
index df1ce95b31655..0000000000000
--- a/x-pack/legacy/server/lib/create_router/call_with_request_factory/call_with_request_factory.js
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export const callWithRequestFactory = (server, pluginId, config) => {
-  const { callWithRequest } = config
-    ? server.plugins.elasticsearch.createCluster(pluginId, config)
-    : server.plugins.elasticsearch.getCluster('data');
-  return callWithRequest;
-};
diff --git a/x-pack/legacy/server/lib/create_router/call_with_request_factory/index.d.ts b/x-pack/legacy/server/lib/create_router/call_with_request_factory/index.d.ts
deleted file mode 100644
index 3537d1bf42079..0000000000000
--- a/x-pack/legacy/server/lib/create_router/call_with_request_factory/index.d.ts
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { Legacy } from 'kibana';
-import { LegacyAPICaller } from '../../../../../../src/core/server';
-
-export type CallWithRequest = (...args: any[]) => LegacyAPICaller;
-
-export declare function callWithRequestFactory(
-  server: Legacy.Server,
-  pluginId: string,
-  config?: {
-    plugins: any[];
-  }
-): CallWithRequest;
diff --git a/x-pack/legacy/server/lib/create_router/call_with_request_factory/index.js b/x-pack/legacy/server/lib/create_router/call_with_request_factory/index.js
deleted file mode 100644
index 787814d87dff9..0000000000000
--- a/x-pack/legacy/server/lib/create_router/call_with_request_factory/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { callWithRequestFactory } from './call_with_request_factory';
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_custom_error.js b/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_custom_error.js
deleted file mode 100644
index f9c102be7a1ff..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_custom_error.js
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { wrapCustomError } from '../wrap_custom_error';
-
-describe('wrap_custom_error', () => {
-  describe('#wrapCustomError', () => {
-    it('should return a Boom object', () => {
-      const originalError = new Error('I am an error');
-      const statusCode = 404;
-      const wrappedError = wrapCustomError(originalError, statusCode);
-
-      expect(wrappedError.isBoom).to.be(true);
-      expect(wrappedError.output.statusCode).to.equal(statusCode);
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_es_error.js b/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_es_error.js
deleted file mode 100644
index 8241dc4329137..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_es_error.js
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { wrapEsError } from '../wrap_es_error';
-
-describe('wrap_es_error', () => {
-  describe('#wrapEsError', () => {
-    let originalError;
-    beforeEach(() => {
-      originalError = new Error('I am an error');
-      originalError.statusCode = 404;
-      originalError.response = '{}';
-    });
-
-    it('should return a Boom object', () => {
-      const wrappedError = wrapEsError(originalError);
-
-      expect(wrappedError.isBoom).to.be(true);
-    });
-
-    it('should return the correct Boom object', () => {
-      const wrappedError = wrapEsError(originalError);
-
-      expect(wrappedError.output.statusCode).to.be(originalError.statusCode);
-      expect(wrappedError.output.payload.message).to.be(originalError.message);
-    });
-
-    it('should return the correct Boom object with custom message', () => {
-      const wrappedError = wrapEsError(originalError, { 404: 'No encontrado!' });
-
-      expect(wrappedError.output.statusCode).to.be(originalError.statusCode);
-      expect(wrappedError.output.payload.message).to.be('No encontrado!');
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_unknown_error.js b/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_unknown_error.js
deleted file mode 100644
index 85e0b2b3033ad..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/__tests__/wrap_unknown_error.js
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { wrapUnknownError } from '../wrap_unknown_error';
-
-describe('wrap_unknown_error', () => {
-  describe('#wrapUnknownError', () => {
-    it('should return a Boom object', () => {
-      const originalError = new Error('I am an error');
-      const wrappedError = wrapUnknownError(originalError);
-
-      expect(wrappedError.isBoom).to.be(true);
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/index.d.ts b/x-pack/legacy/server/lib/create_router/error_wrappers/index.d.ts
deleted file mode 100644
index 1aaefb4e3727c..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/index.d.ts
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-import Boom from 'boom';
-
-export declare function wrapCustomError(error: Error, statusCode: number): Boom<null>;
-
-export declare function wrapEsError(error: Error, statusCodeToMessageMap?: object): Boom<null>;
-
-export declare function wrapUnknownError(error: Error): Boom<null>;
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/index.js b/x-pack/legacy/server/lib/create_router/error_wrappers/index.js
deleted file mode 100644
index f275f15637091..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/index.js
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { wrapCustomError } from './wrap_custom_error';
-export { wrapEsError } from './wrap_es_error';
-export { wrapUnknownError } from './wrap_unknown_error';
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_custom_error.js b/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_custom_error.js
deleted file mode 100644
index 3295113d38ee5..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_custom_error.js
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import Boom from 'boom';
-
-/**
- * Wraps a custom error into a Boom error response and returns it
- *
- * @param err Object error
- * @param statusCode Error status code
- * @return Object Boom error response
- */
-export function wrapCustomError(err, statusCode) {
-  return Boom.boomify(err, { statusCode });
-}
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_es_error.js b/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_es_error.js
deleted file mode 100644
index 72be6321af8a2..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_es_error.js
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import Boom from 'boom';
-
-function extractCausedByChain(causedBy = {}, accumulator = []) {
-  const { reason, caused_by } = causedBy; // eslint-disable-line camelcase
-
-  if (reason) {
-    accumulator.push(reason);
-  }
-
-  // eslint-disable-next-line camelcase
-  if (caused_by) {
-    return extractCausedByChain(caused_by, accumulator);
-  }
-
-  return accumulator;
-}
-
-/**
- * Wraps an error thrown by the ES JS client into a Boom error response and returns it
- *
- * @param err Object Error thrown by ES JS client
- * @param statusCodeToMessageMap Object Optional map of HTTP status codes => error messages
- * @return Object Boom error response
- */
-export function wrapEsError(err, statusCodeToMessageMap = {}) {
-  const { statusCode, response } = err;
-
-  const {
-    error: {
-      root_cause = [], // eslint-disable-line camelcase
-      caused_by, // eslint-disable-line camelcase
-    } = {},
-  } = JSON.parse(response);
-
-  // If no custom message if specified for the error's status code, just
-  // wrap the error as a Boom error response, include the additional information from ES, and return it
-  if (!statusCodeToMessageMap[statusCode]) {
-    const boomError = Boom.boomify(err, { statusCode });
-
-    // The caused_by chain has the most information so use that if it's available. If not then
-    // settle for the root_cause.
-    const causedByChain = extractCausedByChain(caused_by);
-    const defaultCause = root_cause.length ? extractCausedByChain(root_cause[0]) : undefined;
-
-    boomError.output.payload.cause = causedByChain.length ? causedByChain : defaultCause;
-    return boomError;
-  }
-
-  // Otherwise, use the custom message to create a Boom error response and
-  // return it
-  const message = statusCodeToMessageMap[statusCode];
-  return new Boom(message, { statusCode });
-}
diff --git a/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_unknown_error.js b/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_unknown_error.js
deleted file mode 100644
index ffd915c513362..0000000000000
--- a/x-pack/legacy/server/lib/create_router/error_wrappers/wrap_unknown_error.js
+++ /dev/null
@@ -1,17 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import Boom from 'boom';
-
-/**
- * Wraps an unknown error into a Boom error response and returns it
- *
- * @param err Object Unknown error
- * @return Object Boom error response
- */
-export function wrapUnknownError(err) {
-  return Boom.boomify(err);
-}
diff --git a/x-pack/legacy/server/lib/create_router/index.d.ts b/x-pack/legacy/server/lib/create_router/index.d.ts
deleted file mode 100644
index 76e5f4b599708..0000000000000
--- a/x-pack/legacy/server/lib/create_router/index.d.ts
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-import { Request, ResponseToolkit } from 'hapi';
-import { Legacy } from 'kibana';
-import { CallWithRequest } from './call_with_request_factory';
-
-export * from './error_wrappers';
-
-export type RouterRouteHandler = (
-  req: Request,
-  callWithRequest: ReturnType<CallWithRequest>,
-  responseToolkit: ResponseToolkit
-) => Promise<any>;
-
-export type RouterRoute = (path: string, handler: RouterRouteHandler) => Router;
-
-export interface Router {
-  get: RouterRoute;
-  post: RouterRoute;
-  put: RouterRoute;
-  delete: RouterRoute;
-  patch: RouterRoute;
-  isEsError: any;
-}
-
-export declare function createRouter(
-  server: Legacy.Server,
-  pluginId: string,
-  apiBasePath: string,
-  config?: {
-    plugins: any[];
-  }
-): Router;
-
-export declare function isEsErrorFactory(server: Legacy.Server): any;
diff --git a/x-pack/legacy/server/lib/create_router/index.js b/x-pack/legacy/server/lib/create_router/index.js
deleted file mode 100644
index e4d66bdb5a48b..0000000000000
--- a/x-pack/legacy/server/lib/create_router/index.js
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-import Boom from 'boom';
-import { callWithRequestFactory } from './call_with_request_factory';
-import { isEsErrorFactory as createIsEsError } from './is_es_error_factory';
-import { wrapEsError, wrapUnknownError } from './error_wrappers';
-import { licensePreRoutingFactory } from './license_pre_routing_factory';
-
-export { wrapEsError, wrapUnknownError, wrapCustomError } from './error_wrappers';
-
-// Sometimes consumers will need to check if errors are ES errors, too.
-export const isEsErrorFactory = (server) => {
-  return createIsEsError(server);
-};
-
-export const createRouter = (server, pluginId, apiBasePath = '', config) => {
-  const isEsError = isEsErrorFactory(server);
-
-  // NOTE: The license-checking logic depends on the xpack_main plugin, so if your plugin
-  // consumes this helper, make sure it declares 'xpack_main' as a dependency.
-  const licensePreRouting = licensePreRoutingFactory(server, pluginId);
-
-  const callWithRequestInstance = callWithRequestFactory(server, pluginId, config);
-
-  const requestHandler = (handler) => async (request, h) => {
-    try {
-      const callWithRequest = (...args) => {
-        return callWithRequestInstance(request, ...args);
-      };
-      return await handler(request, callWithRequest, h);
-    } catch (err) {
-      if (err instanceof Boom) {
-        throw err;
-      }
-
-      if (isEsError(err)) {
-        throw wrapEsError(err);
-      }
-
-      throw wrapUnknownError(err);
-    }
-  };
-
-  // Decorate base router with HTTP methods.
-  return ['get', 'post', 'put', 'delete', 'patch'].reduce((router, methodName) => {
-    router[methodName] = (subPath, handler) => {
-      const method = methodName.toUpperCase();
-      const path = apiBasePath + subPath;
-      server.route({
-        path,
-        method,
-        handler: requestHandler(handler),
-        config: { pre: [licensePreRouting] },
-      });
-    };
-    return router;
-  }, {});
-};
diff --git a/x-pack/legacy/server/lib/create_router/is_es_error_factory/__tests__/is_es_error_factory.js b/x-pack/legacy/server/lib/create_router/is_es_error_factory/__tests__/is_es_error_factory.js
deleted file mode 100644
index ef6fbaf9c53d0..0000000000000
--- a/x-pack/legacy/server/lib/create_router/is_es_error_factory/__tests__/is_es_error_factory.js
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { isEsErrorFactory } from '../is_es_error_factory';
-import { set } from '@elastic/safer-lodash-set';
-
-class MockAbstractEsError {}
-
-describe('is_es_error_factory', () => {
-  let mockServer;
-  let isEsError;
-
-  beforeEach(() => {
-    const mockEsErrors = {
-      _Abstract: MockAbstractEsError,
-    };
-    mockServer = {};
-    set(mockServer, 'plugins.elasticsearch.getCluster', () => ({ errors: mockEsErrors }));
-
-    isEsError = isEsErrorFactory(mockServer);
-  });
-
-  describe('#isEsErrorFactory', () => {
-    it('should return a function', () => {
-      expect(isEsError).to.be.a(Function);
-    });
-
-    describe('returned function', () => {
-      it('should return true if passed-in err is a known esError', () => {
-        const knownEsError = new MockAbstractEsError();
-        expect(isEsError(knownEsError)).to.be(true);
-      });
-
-      it('should return false if passed-in err is not a known esError', () => {
-        const unknownEsError = {};
-        expect(isEsError(unknownEsError)).to.be(false);
-      });
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/create_router/is_es_error_factory/index.js b/x-pack/legacy/server/lib/create_router/is_es_error_factory/index.js
deleted file mode 100644
index 441648a8701e0..0000000000000
--- a/x-pack/legacy/server/lib/create_router/is_es_error_factory/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { isEsErrorFactory } from './is_es_error_factory';
diff --git a/x-pack/legacy/server/lib/create_router/is_es_error_factory/is_es_error_factory.js b/x-pack/legacy/server/lib/create_router/is_es_error_factory/is_es_error_factory.js
deleted file mode 100644
index 80daac5bd496d..0000000000000
--- a/x-pack/legacy/server/lib/create_router/is_es_error_factory/is_es_error_factory.js
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { memoize } from 'lodash';
-
-const esErrorsFactory = memoize((server) => {
-  return server.plugins.elasticsearch.getCluster('admin').errors;
-});
-
-export function isEsErrorFactory(server) {
-  const esErrors = esErrorsFactory(server);
-  return function isEsError(err) {
-    return err instanceof esErrors._Abstract;
-  };
-}
diff --git a/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/__tests__/license_pre_routing_factory.js b/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/__tests__/license_pre_routing_factory.js
deleted file mode 100644
index dde18a0ccd7dd..0000000000000
--- a/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/__tests__/license_pre_routing_factory.js
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { licensePreRoutingFactory } from '../license_pre_routing_factory';
-import { LICENSE_STATUS_INVALID, LICENSE_STATUS_VALID } from '../../../../../common/constants';
-
-describe('license_pre_routing_factory', () => {
-  describe('#reportingFeaturePreRoutingFactory', () => {
-    let mockServer;
-    let mockLicenseCheckResults;
-
-    beforeEach(() => {
-      mockServer = {
-        plugins: {
-          xpack_main: {
-            info: {
-              feature: () => ({
-                getLicenseCheckResults: () => mockLicenseCheckResults,
-              }),
-            },
-          },
-        },
-      };
-    });
-
-    it('instantiates a new instance per plugin', () => {
-      const firstInstance = licensePreRoutingFactory(mockServer, 'foo');
-      const secondInstance = licensePreRoutingFactory(mockServer, 'bar');
-
-      expect(firstInstance).to.not.be(secondInstance);
-    });
-
-    describe('status is invalid', () => {
-      beforeEach(() => {
-        mockLicenseCheckResults = {
-          status: LICENSE_STATUS_INVALID,
-        };
-      });
-
-      it('replies with 403', () => {
-        const licensePreRouting = licensePreRoutingFactory(mockServer);
-        const stubRequest = {};
-        expect(() => licensePreRouting(stubRequest)).to.throwException((response) => {
-          expect(response).to.be.an(Error);
-          expect(response.isBoom).to.be(true);
-          expect(response.output.statusCode).to.be(403);
-        });
-      });
-    });
-
-    describe('status is valid', () => {
-      beforeEach(() => {
-        mockLicenseCheckResults = {
-          status: LICENSE_STATUS_VALID,
-        };
-      });
-
-      it('replies with nothing', () => {
-        const licensePreRouting = licensePreRoutingFactory(mockServer);
-        const stubRequest = {};
-        const response = licensePreRouting(stubRequest);
-        expect(response).to.be(null);
-      });
-    });
-  });
-});
diff --git a/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/index.js b/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/index.js
deleted file mode 100644
index 0743e443955f4..0000000000000
--- a/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { licensePreRoutingFactory } from './license_pre_routing_factory';
diff --git a/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/license_pre_routing_factory.js b/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/license_pre_routing_factory.js
deleted file mode 100644
index 81640ebb35ea9..0000000000000
--- a/x-pack/legacy/server/lib/create_router/license_pre_routing_factory/license_pre_routing_factory.js
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { wrapCustomError } from '../error_wrappers';
-import { LICENSE_STATUS_VALID } from '../../../../common/constants';
-
-export const licensePreRoutingFactory = (server, pluginId) => {
-  return () => {
-    const xpackMainPlugin = server.plugins.xpack_main;
-    const licenseCheckResults = xpackMainPlugin.info.feature(pluginId).getLicenseCheckResults();
-
-    // Apps which don't have any license restrictions will return undefined license check results.
-    if (licenseCheckResults) {
-      if (licenseCheckResults.status !== LICENSE_STATUS_VALID) {
-        const error = new Error(licenseCheckResults.message);
-        const statusCode = 403;
-        throw wrapCustomError(error, statusCode);
-      }
-    }
-
-    return null;
-  };
-};
diff --git a/x-pack/legacy/server/lib/key_case_converter.js b/x-pack/legacy/server/lib/key_case_converter.js
deleted file mode 100644
index aea9a90302c3e..0000000000000
--- a/x-pack/legacy/server/lib/key_case_converter.js
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import _ from 'lodash';
-
-// Note: This function uses _.clone. This will clone objects created by constructors other than Object
-// to plain Object objects. Uncloneable values such as functions, DOM nodes, Maps, Sets, and WeakMaps
-// will be cloned to the empty object.
-function convertKeysToSpecifiedCaseDeep(object, caseConversionFunction) {
-  // Base case
-  if (!(_.isPlainObject(object) || _.isArray(object))) {
-    return object;
-  }
-
-  // Clone (so we don't modify the original object that was passed in)
-  let newObject;
-  if (Array.isArray(object)) {
-    newObject = object.slice(0);
-  } else {
-    newObject = _.clone(object);
-
-    // Convert top-level keys
-    newObject = _.mapKeys(newObject, (value, key) => caseConversionFunction(key)); // eslint-disable-line no-unused-vars
-  }
-
-  // Recursively convert nested object keys
-  _.forEach(
-    newObject,
-    (value, key) => (newObject[key] = convertKeysToSpecifiedCaseDeep(value, caseConversionFunction))
-  );
-
-  return newObject;
-}
-
-function validateObject(object) {
-  if (!(_.isPlainObject(object) || _.isArray(object))) {
-    throw new Error('Specified object should be an Object or Array');
-  }
-}
-
-export function convertKeysToSnakeCaseDeep(object) {
-  validateObject(object);
-  return convertKeysToSpecifiedCaseDeep(object, _.snakeCase);
-}
-
-export function convertKeysToCamelCaseDeep(object) {
-  validateObject(object);
-  return convertKeysToSpecifiedCaseDeep(object, _.camelCase);
-}
diff --git a/x-pack/legacy/server/lib/parse_kibana_state.js b/x-pack/legacy/server/lib/parse_kibana_state.js
deleted file mode 100644
index a6c9bfbb511c1..0000000000000
--- a/x-pack/legacy/server/lib/parse_kibana_state.js
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { set } from '@elastic/safer-lodash-set';
-import { isPlainObject, omit, get } from 'lodash';
-import rison from 'rison-node';
-
-const stateTypeKeys = {
-  global: '_g',
-  app: '_a',
-};
-
-class KibanaState {
-  constructor(query, type = 'global') {
-    const propId = stateTypeKeys[type];
-    if (!isPlainObject(query)) throw new TypeError('Query parameter must be an object');
-    if (!propId) throw new TypeError(`Unknown state type: '${type}'`);
-
-    const queryValue = query[propId];
-
-    this.exists = Boolean(queryValue);
-    this.state = queryValue ? rison.decode(queryValue) : {};
-    this.type = type;
-  }
-
-  removeProps(props) {
-    this.state = omit(this.state, props);
-  }
-
-  get(prop, defVal) {
-    return get(this.state, prop, defVal);
-  }
-
-  set(prop, val) {
-    return set(this.state, prop, val);
-  }
-
-  toString() {
-    return rison.encode(this.state);
-  }
-
-  toQuery() {
-    const index = stateTypeKeys[this.type];
-    const output = {};
-    output[index] = this.toString();
-    return output;
-  }
-}
-
-export function parseKibanaState(query, type) {
-  return new KibanaState(query, type);
-}
diff --git a/x-pack/legacy/server/lib/register_license_checker/index.d.ts b/x-pack/legacy/server/lib/register_license_checker/index.d.ts
deleted file mode 100644
index 555008921df42..0000000000000
--- a/x-pack/legacy/server/lib/register_license_checker/index.d.ts
+++ /dev/null
@@ -1,15 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { Legacy } from 'kibana';
-import { LicenseType } from '../../../common/constants';
-
-export declare function registerLicenseChecker(
-  server: Legacy.Server,
-  pluginId: string,
-  pluginName: string,
-  minimumLicenseRequired: LicenseType
-): void;
diff --git a/x-pack/legacy/server/lib/register_license_checker/index.js b/x-pack/legacy/server/lib/register_license_checker/index.js
deleted file mode 100644
index 7b0f97c38d129..0000000000000
--- a/x-pack/legacy/server/lib/register_license_checker/index.js
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export { registerLicenseChecker } from './register_license_checker';
diff --git a/x-pack/legacy/server/lib/register_license_checker/register_license_checker.js b/x-pack/legacy/server/lib/register_license_checker/register_license_checker.js
deleted file mode 100644
index 57cbe30c25cb2..0000000000000
--- a/x-pack/legacy/server/lib/register_license_checker/register_license_checker.js
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { pairwise } from 'rxjs/operators';
-
-import { ServiceStatusLevels } from '../../../../../src/core/server';
-import { checkLicense } from '../check_license';
-
-export function registerLicenseChecker(server, pluginId, pluginName, minimumLicenseRequired) {
-  const xpackMainPlugin = server.plugins.xpack_main;
-  const subscription = server.newPlatform.setup.core.status.core$
-    .pipe(pairwise())
-    .subscribe(([coreLast, coreCurrent]) => {
-      if (
-        !subscription.closed &&
-        coreLast.elasticsearch.level !== ServiceStatusLevels.available &&
-        coreCurrent.elasticsearch.level === ServiceStatusLevels.available
-      ) {
-        // Unsubscribe as soon as ES becomes available so this function only runs once
-        subscription.unsubscribe();
-
-        // Register a function that is called whenever the xpack info changes,
-        // to re-compute the license check results for this plugin
-        xpackMainPlugin.info
-          .feature(pluginId)
-          .registerLicenseCheckResultsGenerator((xpackLicenseInfo) => {
-            return checkLicense(pluginName, minimumLicenseRequired, xpackLicenseInfo);
-          });
-      }
-    });
-}
diff --git a/x-pack/legacy/server/lib/watch_status_and_license_to_initialize.js b/x-pack/legacy/server/lib/watch_status_and_license_to_initialize.js
deleted file mode 100644
index 71fc54091a6e1..0000000000000
--- a/x-pack/legacy/server/lib/watch_status_and_license_to_initialize.js
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-import * as Rx from 'rxjs';
-import { catchError, mergeMap, map, switchMap, tap } from 'rxjs/operators';
-
-export const RETRY_SCALE_DURATION = 100;
-export const RETRY_DURATION_MAX = 10000;
-
-const calculateDuration = (i) => {
-  const duration = i * RETRY_SCALE_DURATION;
-  if (duration > RETRY_DURATION_MAX) {
-    return RETRY_DURATION_MAX;
-  }
-
-  return duration;
-};
-
-// we can't use a retryWhen here, because we want to propagate the red status and then retry
-const propagateRedStatusAndScaleRetry = () => {
-  let i = 0;
-  return (err, caught) =>
-    Rx.concat(
-      Rx.of({
-        state: 'red',
-        message: err.message,
-      }),
-      Rx.timer(calculateDuration(++i)).pipe(mergeMap(() => caught))
-    );
-};
-
-export function watchStatusAndLicenseToInitialize(xpackMainPlugin, downstreamPlugin, initialize) {
-  const xpackInfo = xpackMainPlugin.info;
-  const xpackInfoFeature = xpackInfo.feature(downstreamPlugin.id);
-
-  const upstreamStatus = xpackMainPlugin.status;
-  const currentStatus$ = Rx.of({
-    state: upstreamStatus.state,
-    message: upstreamStatus.message,
-  });
-  const newStatus$ = Rx.fromEvent(
-    upstreamStatus,
-    'change',
-    null,
-    (previousState, previousMsg, state, message) => {
-      // eslint-disable-line no-unused-vars
-      return {
-        state,
-        message,
-      };
-    }
-  );
-  const status$ = Rx.merge(currentStatus$, newStatus$);
-
-  const currentLicense$ = Rx.of(xpackInfoFeature.getLicenseCheckResults());
-  const newLicense$ = Rx.fromEventPattern(xpackInfo.onLicenseInfoChange.bind(xpackInfo)).pipe(
-    map(() => xpackInfoFeature.getLicenseCheckResults())
-  );
-  const license$ = Rx.merge(currentLicense$, newLicense$);
-
-  Rx.combineLatest(status$, license$)
-    .pipe(
-      map(([status, license]) => ({ status, license })),
-      switchMap(({ status, license }) => {
-        if (status.state !== 'green') {
-          return Rx.of({ state: status.state, message: status.message });
-        }
-
-        return Rx.defer(() => initialize(license)).pipe(
-          map(() => ({
-            state: 'green',
-            message: 'Ready',
-          })),
-          catchError(propagateRedStatusAndScaleRetry())
-        );
-      }),
-      tap(({ state, message }) => {
-        downstreamPlugin.status[state](message);
-      })
-    )
-    .subscribe();
-}
diff --git a/x-pack/legacy/server/lib/watch_status_and_license_to_initialize.test.js b/x-pack/legacy/server/lib/watch_status_and_license_to_initialize.test.js
deleted file mode 100644
index 33282b7591db7..0000000000000
--- a/x-pack/legacy/server/lib/watch_status_and_license_to_initialize.test.js
+++ /dev/null
@@ -1,301 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import { EventEmitter } from 'events';
-import {
-  watchStatusAndLicenseToInitialize,
-  RETRY_SCALE_DURATION,
-  RETRY_DURATION_MAX,
-} from './watch_status_and_license_to_initialize';
-
-const createMockXpackMainPluginAndFeature = (featureId) => {
-  const licenseChangeCallbacks = [];
-
-  const mockFeature = {
-    getLicenseCheckResults: jest.fn(),
-    mock: {
-      triggerLicenseChange: () => {
-        for (const callback of licenseChangeCallbacks) {
-          callback();
-        }
-      },
-      setLicenseCheckResults: (value) => {
-        mockFeature.getLicenseCheckResults.mockReturnValue(value);
-      },
-    },
-  };
-
-  const mockXpackMainPlugin = {
-    info: {
-      onLicenseInfoChange: (callback) => {
-        licenseChangeCallbacks.push(callback);
-      },
-      feature: (id) => {
-        if (id === featureId) {
-          return mockFeature;
-        }
-        throw new Error('Unexpected feature');
-      },
-    },
-    status: new EventEmitter(),
-    mock: {
-      setStatus: (state, message) => {
-        mockXpackMainPlugin.status.state = state;
-        mockXpackMainPlugin.status.message = message;
-        mockXpackMainPlugin.status.emit('change', null, null, state, message);
-      },
-    },
-  };
-
-  return { mockXpackMainPlugin, mockFeature };
-};
-
-const createMockDownstreamPlugin = (id) => {
-  const defaultImplementation = () => {
-    throw new Error('Not implemented');
-  };
-  return {
-    id,
-    status: {
-      disabled: jest.fn().mockImplementation(defaultImplementation),
-      yellow: jest.fn().mockImplementation(defaultImplementation),
-      green: jest.fn().mockImplementation(defaultImplementation),
-      red: jest.fn().mockImplementation(defaultImplementation),
-    },
-  };
-};
-
-const advanceRetry = async (initializeCount) => {
-  await Promise.resolve();
-  let duration = initializeCount * RETRY_SCALE_DURATION;
-  if (duration > RETRY_DURATION_MAX) {
-    duration = RETRY_DURATION_MAX;
-  }
-  jest.advanceTimersByTime(duration);
-};
-
-['red', 'yellow', 'disabled'].forEach((state) => {
-  test(`mirrors ${state} immediately`, () => {
-    const pluginId = 'foo-plugin';
-    const message = `${state} is now the state`;
-    const { mockXpackMainPlugin } = createMockXpackMainPluginAndFeature(pluginId);
-    mockXpackMainPlugin.mock.setStatus(state, message);
-    const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-    const initializeMock = jest.fn();
-    downstreamPlugin.status[state].mockImplementation(() => {});
-
-    watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-
-    expect(initializeMock).not.toHaveBeenCalled();
-    expect(downstreamPlugin.status[state]).toHaveBeenCalledTimes(1);
-    expect(downstreamPlugin.status[state]).toHaveBeenCalledWith(message);
-  });
-});
-
-test(`calls initialize and doesn't immediately set downstream status when the initial status is green`, () => {
-  const pluginId = 'foo-plugin';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green', 'green is now the state');
-  const licenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(licenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-  const initializeMock = jest.fn().mockImplementation(() => new Promise(() => {}));
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-
-  expect(initializeMock).toHaveBeenCalledTimes(1);
-  expect(initializeMock).toHaveBeenCalledWith(licenseCheckResults);
-  expect(downstreamPlugin.status.green).toHaveBeenCalledTimes(0);
-});
-
-test(`sets downstream plugin's status to green when initialize resolves`, (done) => {
-  const pluginId = 'foo-plugin';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green', 'green is now the state');
-  const licenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(licenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-  const initializeMock = jest.fn().mockImplementation(() => Promise.resolve());
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-
-  expect(initializeMock).toHaveBeenCalledTimes(1);
-  expect(initializeMock).toHaveBeenCalledWith(licenseCheckResults);
-  downstreamPlugin.status.green.mockImplementation((actualMessage) => {
-    expect(actualMessage).toBe('Ready');
-    done();
-  });
-});
-
-test(`sets downstream plugin's status to red when initialize initially rejects, and continually polls initialize`, (done) => {
-  jest.useFakeTimers();
-
-  const pluginId = 'foo-plugin';
-  const errorMessage = 'the error message';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green');
-  const licenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(licenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-
-  let isRed = false;
-  let initializeCount = 0;
-  const initializeMock = jest.fn().mockImplementation(() => {
-    ++initializeCount;
-
-    // on the second retry, ensure we already set the status to red
-    if (initializeCount === 2) {
-      expect(isRed).toBe(true);
-    }
-
-    // this should theoretically continue indefinitely, but we only have so long to run the tests
-    if (initializeCount === 100) {
-      done();
-    }
-
-    // everytime this is called, we have to wait for a new promise to be resolved
-    // allowing the Promise the we return below to run, and then advance the timers
-    setImmediate(() => {
-      advanceRetry(initializeCount);
-    });
-    return Promise.reject(new Error(errorMessage));
-  });
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-
-  expect(initializeMock).toHaveBeenCalledTimes(1);
-  expect(initializeMock).toHaveBeenCalledWith(licenseCheckResults);
-  downstreamPlugin.status.red.mockImplementation((message) => {
-    isRed = true;
-    expect(message).toBe(errorMessage);
-  });
-});
-
-test(`sets downstream plugin's status to green when initialize resolves after rejecting 10 times`, (done) => {
-  jest.useFakeTimers();
-
-  const pluginId = 'foo-plugin';
-  const errorMessage = 'the error message';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green');
-  const licenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(licenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-
-  let initializeCount = 0;
-  const initializeMock = jest.fn().mockImplementation(() => {
-    ++initializeCount;
-
-    // everytime this is called, we have to wait for a new promise to be resolved
-    // allowing the Promise the we return below to run, and then advance the timers
-    setImmediate(() => {
-      advanceRetry(initializeCount);
-    });
-
-    if (initializeCount >= 10) {
-      return Promise.resolve();
-    }
-
-    return Promise.reject(new Error(errorMessage));
-  });
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-
-  expect(initializeMock).toHaveBeenCalledTimes(1);
-  expect(initializeMock).toHaveBeenCalledWith(licenseCheckResults);
-  downstreamPlugin.status.red.mockImplementation((message) => {
-    expect(initializeCount).toBeLessThan(10);
-    expect(message).toBe(errorMessage);
-  });
-  downstreamPlugin.status.green.mockImplementation((message) => {
-    expect(initializeCount).toBe(10);
-    expect(message).toBe('Ready');
-    done();
-  });
-});
-
-test(`calls initialize twice when it gets a new license and the status is green`, (done) => {
-  const pluginId = 'foo-plugin';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green');
-  const firstLicenseCheckResults = Symbol();
-  const secondLicenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(firstLicenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-  const initializeMock = jest.fn().mockImplementation(() => Promise.resolve());
-
-  let count = 0;
-  downstreamPlugin.status.green.mockImplementation((message) => {
-    expect(message).toBe('Ready');
-    ++count;
-    if (count === 1) {
-      mockFeature.mock.setLicenseCheckResults(secondLicenseCheckResults);
-      mockFeature.mock.triggerLicenseChange();
-    }
-    if (count === 2) {
-      expect(initializeMock).toHaveBeenCalledWith(firstLicenseCheckResults);
-      expect(initializeMock).toHaveBeenCalledWith(secondLicenseCheckResults);
-      expect(initializeMock).toHaveBeenCalledTimes(2);
-      done();
-    }
-  });
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-});
-
-test(`doesn't call initialize twice when it gets a new license when the status isn't green`, (done) => {
-  const pluginId = 'foo-plugin';
-  const redMessage = 'the red message';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green');
-  const firstLicenseCheckResults = Symbol();
-  const secondLicenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(firstLicenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-  const initializeMock = jest.fn().mockImplementation(() => Promise.resolve());
-
-  downstreamPlugin.status.green.mockImplementation((message) => {
-    expect(message).toBe('Ready');
-    mockXpackMainPlugin.mock.setStatus('red', redMessage);
-    mockFeature.mock.setLicenseCheckResults(secondLicenseCheckResults);
-    mockFeature.mock.triggerLicenseChange();
-  });
-
-  downstreamPlugin.status.red.mockImplementation((message) => {
-    expect(message).toBe(redMessage);
-    expect(initializeMock).toHaveBeenCalledTimes(1);
-    expect(initializeMock).toHaveBeenCalledWith(firstLicenseCheckResults);
-    done();
-  });
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-});
-
-test(`calls initialize twice when the status changes to green twice`, (done) => {
-  const pluginId = 'foo-plugin';
-  const { mockXpackMainPlugin, mockFeature } = createMockXpackMainPluginAndFeature(pluginId);
-  mockXpackMainPlugin.mock.setStatus('green');
-  const licenseCheckResults = Symbol();
-  mockFeature.mock.setLicenseCheckResults(licenseCheckResults);
-  const downstreamPlugin = createMockDownstreamPlugin(pluginId);
-  const initializeMock = jest.fn().mockImplementation(() => Promise.resolve());
-
-  let count = 0;
-  downstreamPlugin.status.green.mockImplementation((message) => {
-    expect(message).toBe('Ready');
-    ++count;
-    if (count === 1) {
-      mockXpackMainPlugin.mock.setStatus('green');
-    }
-    if (count === 2) {
-      expect(initializeMock).toHaveBeenCalledWith(licenseCheckResults);
-      expect(initializeMock).toHaveBeenCalledTimes(2);
-      done();
-    }
-  });
-
-  watchStatusAndLicenseToInitialize(mockXpackMainPlugin, downstreamPlugin, initializeMock);
-});
diff --git a/x-pack/legacy/server/lib/xpack_usage.js b/x-pack/legacy/server/lib/xpack_usage.js
deleted file mode 100644
index 50b50ba18c37f..0000000000000
--- a/x-pack/legacy/server/lib/xpack_usage.js
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-export function xpackUsage(client) {
-  /*
-   * Get an object over the Usage API that as available/enabled data and some
-   * select metadata for each of the X-Pack UI plugins
-   */
-  return client.transport.request({
-    method: 'GET',
-    path: '/_xpack/usage',
-  });
-}
diff --git a/x-pack/plugins/actions/server/constants/plugin.ts b/x-pack/plugins/actions/server/constants/plugin.ts
index 7d20eb6990247..b82464bd92a18 100644
--- a/x-pack/plugins/actions/server/constants/plugin.ts
+++ b/x-pack/plugins/actions/server/constants/plugin.ts
@@ -4,11 +4,11 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { LICENSE_TYPE_BASIC, LicenseType } from '../../../../legacy/common/constants';
+import { LicenseType } from '../../../licensing/server';
 
 export const PLUGIN = {
   ID: 'actions',
-  MINIMUM_LICENSE_REQUIRED: LICENSE_TYPE_BASIC as LicenseType, // TODO: supposed to be changed up on requirements
+  MINIMUM_LICENSE_REQUIRED: 'basic' as LicenseType, // TODO: supposed to be changed up on requirements
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   getI18nName: (i18n: any): string =>
     i18n.translate('xpack.actions.appName', {
diff --git a/x-pack/plugins/alerts/server/constants/plugin.ts b/x-pack/plugins/alerts/server/constants/plugin.ts
index c180b68680841..4e1e0c59e0b48 100644
--- a/x-pack/plugins/alerts/server/constants/plugin.ts
+++ b/x-pack/plugins/alerts/server/constants/plugin.ts
@@ -4,11 +4,11 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { LICENSE_TYPE_BASIC, LicenseType } from '../../../../legacy/common/constants';
+import { LicenseType } from '../../../licensing/server';
 
 export const PLUGIN = {
   ID: 'alerts',
-  MINIMUM_LICENSE_REQUIRED: LICENSE_TYPE_BASIC as LicenseType, // TODO: supposed to be changed up on requirements
+  MINIMUM_LICENSE_REQUIRED: 'basic' as LicenseType, // TODO: supposed to be changed up on requirements
   // all plugins seem to use getI18nName with any
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   getI18nName: (i18n: any): string =>
diff --git a/x-pack/plugins/apm/common/service_health_status.ts b/x-pack/plugins/apm/common/service_health_status.ts
index 468f06ab97af8..1d4bcfb3b0e07 100644
--- a/x-pack/plugins/apm/common/service_health_status.ts
+++ b/x-pack/plugins/apm/common/service_health_status.ts
@@ -7,7 +7,7 @@
 import { i18n } from '@kbn/i18n';
 import { ANOMALY_SEVERITY } from '../../ml/common';
 
-import { EuiTheme } from '../../../legacy/common/eui_styled_components';
+import { EuiTheme } from '../../xpack_legacy/common';
 
 export enum ServiceHealthStatus {
   healthy = 'healthy',
diff --git a/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/custom_metric_form.tsx b/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/custom_metric_form.tsx
index a785cb31c3cf4..262d94d8f3674 100644
--- a/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/custom_metric_form.tsx
+++ b/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/custom_metric_form.tsx
@@ -27,10 +27,7 @@ import {
   SNAPSHOT_CUSTOM_AGGREGATIONS,
   SnapshotCustomAggregationRT,
 } from '../../../../../../../common/http_api/snapshot_api';
-import {
-  EuiTheme,
-  withTheme,
-} from '../../../../../../../../../legacy/common/eui_styled_components';
+import { EuiTheme, withTheme } from '../../../../../../../../xpack_legacy/common';
 
 interface SelectedOption {
   label: string;
diff --git a/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/metrics_edit_mode.tsx b/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/metrics_edit_mode.tsx
index e75885ccbc917..831a0cde49cfb 100644
--- a/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/metrics_edit_mode.tsx
+++ b/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/metrics_edit_mode.tsx
@@ -8,10 +8,7 @@ import { EuiFlexItem, EuiFlexGroup, EuiButtonIcon } from '@elastic/eui';
 import { i18n } from '@kbn/i18n';
 import { getCustomMetricLabel } from '../../../../../../../common/formatters/get_custom_metric_label';
 import { SnapshotCustomMetricInput } from '../../../../../../../common/http_api/snapshot_api';
-import {
-  EuiTheme,
-  withTheme,
-} from '../../../../../../../../../legacy/common/eui_styled_components';
+import { EuiTheme, withTheme } from '../../../../../../../../xpack_legacy/common';
 
 interface Props {
   theme: EuiTheme | undefined;
diff --git a/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/mode_switcher.tsx b/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/mode_switcher.tsx
index d1abcade5d660..956241545e8be 100644
--- a/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/mode_switcher.tsx
+++ b/x-pack/plugins/infra/public/pages/metrics/inventory_view/components/waffle/metric_control/mode_switcher.tsx
@@ -9,10 +9,7 @@ import { i18n } from '@kbn/i18n';
 import { FormattedMessage } from '@kbn/i18n/react';
 import { CustomMetricMode } from './types';
 import { SnapshotCustomMetricInput } from '../../../../../../../common/http_api/snapshot_api';
-import {
-  EuiTheme,
-  withTheme,
-} from '../../../../../../../../../legacy/common/eui_styled_components';
+import { EuiTheme, withTheme } from '../../../../../../../../xpack_legacy/common';
 
 interface Props {
   theme: EuiTheme | undefined;
diff --git a/x-pack/plugins/ingest_manager/public/applications/ingest_manager/index.tsx b/x-pack/plugins/ingest_manager/public/applications/ingest_manager/index.tsx
index 5520a50463db4..69fb2ff6f9506 100644
--- a/x-pack/plugins/ingest_manager/public/applications/ingest_manager/index.tsx
+++ b/x-pack/plugins/ingest_manager/public/applications/ingest_manager/index.tsx
@@ -12,7 +12,7 @@ import { FormattedMessage } from '@kbn/i18n/react';
 import styled from 'styled-components';
 import { EuiErrorBoundary, EuiPanel, EuiEmptyPrompt, EuiCode } from '@elastic/eui';
 import { CoreStart, AppMountParameters } from 'src/core/public';
-import { EuiThemeProvider } from '../../../../../legacy/common/eui_styled_components';
+import { EuiThemeProvider } from '../../../../xpack_legacy/common';
 import {
   IngestManagerSetupDeps,
   IngestManagerConfigType,
diff --git a/x-pack/plugins/observability/public/application/index.tsx b/x-pack/plugins/observability/public/application/index.tsx
index fa691a7f41ddb..6cb7e8d9cf8fd 100644
--- a/x-pack/plugins/observability/public/application/index.tsx
+++ b/x-pack/plugins/observability/public/application/index.tsx
@@ -9,7 +9,7 @@ import ReactDOM from 'react-dom';
 import { Route, Router, Switch } from 'react-router-dom';
 import { AppMountParameters, CoreStart } from '../../../../../src/core/public';
 import { RedirectAppLinks } from '../../../../../src/plugins/kibana_react/public';
-import { EuiThemeProvider } from '../../../../legacy/common/eui_styled_components';
+import { EuiThemeProvider } from '../../../xpack_legacy/common';
 import { PluginContext } from '../context/plugin_context';
 import { usePluginContext } from '../hooks/use_plugin_context';
 import { useRouteParams } from '../hooks/use_route_params';
diff --git a/x-pack/plugins/observability/public/hooks/use_theme.tsx b/x-pack/plugins/observability/public/hooks/use_theme.tsx
index d0449a4432d93..51a1ad5029538 100644
--- a/x-pack/plugins/observability/public/hooks/use_theme.tsx
+++ b/x-pack/plugins/observability/public/hooks/use_theme.tsx
@@ -5,7 +5,7 @@
  */
 import { useContext } from 'react';
 import { ThemeContext } from 'styled-components';
-import { EuiTheme } from '../../../../legacy/common/eui_styled_components';
+import { EuiTheme } from '../../../xpack_legacy/common';
 
 export function useTheme() {
   const theme: EuiTheme = useContext(ThemeContext);
diff --git a/x-pack/plugins/security_solution/public/common/mock/endpoint/app_root_provider.tsx b/x-pack/plugins/security_solution/public/common/mock/endpoint/app_root_provider.tsx
index 73c0f00573911..3b7262e8a8d7e 100644
--- a/x-pack/plugins/security_solution/public/common/mock/endpoint/app_root_provider.tsx
+++ b/x-pack/plugins/security_solution/public/common/mock/endpoint/app_root_provider.tsx
@@ -11,7 +11,7 @@ import { Router } from 'react-router-dom';
 import { History } from 'history';
 import { useObservable } from 'react-use';
 import { Store } from 'redux';
-import { EuiThemeProvider } from '../../../../../../legacy/common/eui_styled_components';
+import { EuiThemeProvider } from '../../../../../xpack_legacy/common';
 import { KibanaContextProvider } from '../../../../../../../src/plugins/kibana_react/public';
 import { RouteCapture } from '../../components/endpoint/route_capture';
 import { StartPlugins } from '../../../types';
diff --git a/x-pack/plugins/security_solution/public/management/pages/policy/view/vertical_divider.ts b/x-pack/plugins/security_solution/public/management/pages/policy/view/vertical_divider.ts
index 6a3aecb4a6503..b6f5c9b7421b5 100644
--- a/x-pack/plugins/security_solution/public/management/pages/policy/view/vertical_divider.ts
+++ b/x-pack/plugins/security_solution/public/management/pages/policy/view/vertical_divider.ts
@@ -5,7 +5,7 @@
  */
 
 import styled from 'styled-components';
-import { EuiTheme } from '../../../../../../../legacy/common/eui_styled_components';
+import { EuiTheme } from '../../../../../../xpack_legacy/common';
 
 type SpacingOptions = keyof EuiTheme['eui']['spacerSizes'];
 
diff --git a/x-pack/plugins/transform/common/constants.ts b/x-pack/plugins/transform/common/constants.ts
index 5efb6f31c1e3f..f2dbc085ab46f 100644
--- a/x-pack/plugins/transform/common/constants.ts
+++ b/x-pack/plugins/transform/common/constants.ts
@@ -6,7 +6,7 @@
 
 import { i18n } from '@kbn/i18n';
 
-import { LICENSE_TYPE_BASIC, LicenseType } from '../../../legacy/common/constants';
+import { LicenseType } from '../../licensing/common/types';
 
 export const DEFAULT_REFRESH_INTERVAL_MS = 30000;
 export const MINIMUM_REFRESH_INTERVAL_MS = 1000;
@@ -14,7 +14,7 @@ export const PROGRESS_REFRESH_INTERVAL_MS = 2000;
 
 export const PLUGIN = {
   ID: 'transform',
-  MINIMUM_LICENSE_REQUIRED: LICENSE_TYPE_BASIC as LicenseType,
+  MINIMUM_LICENSE_REQUIRED: 'basic' as LicenseType,
   getI18nName: (): string => {
     return i18n.translate('xpack.transform.appName', {
       defaultMessage: 'Transforms',
diff --git a/x-pack/plugins/transform/server/routes/api/error_utils.ts b/x-pack/plugins/transform/server/routes/api/error_utils.ts
index 269cd28c4bda6..ef5927651df88 100644
--- a/x-pack/plugins/transform/server/routes/api/error_utils.ts
+++ b/x-pack/plugins/transform/server/routes/api/error_utils.ts
@@ -4,7 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { boomify, isBoom } from 'boom';
+import Boom from 'boom';
 
 import { i18n } from '@kbn/i18n';
 
@@ -76,10 +76,65 @@ export function fillResultsWithTimeouts({ results, id, items, action }: Params)
 }
 
 export function wrapError(error: any): CustomHttpResponseOptions<ResponseError> {
-  const boom = isBoom(error) ? error : boomify(error, { statusCode: error.status });
+  const boom = Boom.isBoom(error) ? error : Boom.boomify(error, { statusCode: error.status });
   return {
     body: boom,
     headers: boom.output.headers,
     statusCode: boom.output.statusCode,
   };
 }
+
+function extractCausedByChain(
+  causedBy: Record<string, any> = {},
+  accumulator: string[] = []
+): string[] {
+  const { reason, caused_by } = causedBy; // eslint-disable-line @typescript-eslint/naming-convention
+
+  if (reason) {
+    accumulator.push(reason);
+  }
+
+  if (caused_by) {
+    return extractCausedByChain(caused_by, accumulator);
+  }
+
+  return accumulator;
+}
+
+/**
+ * Wraps an error thrown by the ES JS client into a Boom error response and returns it
+ *
+ * @param err Object Error thrown by ES JS client
+ * @param statusCodeToMessageMap Object Optional map of HTTP status codes => error messages
+ * @return Object Boom error response
+ */
+export function wrapEsError(err: any, statusCodeToMessageMap: Record<string, any> = {}) {
+  const { statusCode, response } = err;
+
+  const {
+    error: {
+      root_cause = [], // eslint-disable-line @typescript-eslint/naming-convention
+      caused_by = {}, // eslint-disable-line @typescript-eslint/naming-convention
+    } = {},
+  } = JSON.parse(response);
+
+  // If no custom message if specified for the error's status code, just
+  // wrap the error as a Boom error response, include the additional information from ES, and return it
+  if (!statusCodeToMessageMap[statusCode]) {
+    const boomError = Boom.boomify(err, { statusCode });
+
+    // The caused_by chain has the most information so use that if it's available. If not then
+    // settle for the root_cause.
+    const causedByChain = extractCausedByChain(caused_by);
+    const defaultCause = root_cause.length ? extractCausedByChain(root_cause[0]) : undefined;
+
+    // @ts-expect-error cause is not defined on payload type
+    boomError.output.payload.cause = causedByChain.length ? causedByChain : defaultCause;
+    return boomError;
+  }
+
+  // Otherwise, use the custom message to create a Boom error response and
+  // return it
+  const message = statusCodeToMessageMap[statusCode];
+  return new Boom(message, { statusCode });
+}
diff --git a/x-pack/plugins/transform/server/routes/api/field_histograms.ts b/x-pack/plugins/transform/server/routes/api/field_histograms.ts
index 88352ec4af129..636af095e0053 100644
--- a/x-pack/plugins/transform/server/routes/api/field_histograms.ts
+++ b/x-pack/plugins/transform/server/routes/api/field_histograms.ts
@@ -9,8 +9,6 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { wrapEsError } from '../../../../../legacy/server/lib/create_router/error_wrappers';
-
 import {
   indexPatternTitleSchema,
   IndexPatternTitleSchema,
@@ -24,7 +22,7 @@ import { RouteDependencies } from '../../types';
 
 import { addBasePath } from '../index';
 
-import { wrapError } from './error_utils';
+import { wrapError, wrapEsError } from './error_utils';
 
 export function registerFieldHistogramsRoutes({ router, license }: RouteDependencies) {
   router.post<IndexPatternTitleSchema, undefined, FieldHistogramsRequestSchema>(
diff --git a/x-pack/plugins/transform/server/routes/api/transforms.ts b/x-pack/plugins/transform/server/routes/api/transforms.ts
index 3d2018eb5801f..31b2c2285a764 100644
--- a/x-pack/plugins/transform/server/routes/api/transforms.ts
+++ b/x-pack/plugins/transform/server/routes/api/transforms.ts
@@ -12,7 +12,6 @@ import {
   SavedObjectsClientContract,
   LegacyAPICaller,
 } from 'kibana/server';
-import { wrapEsError } from '../../../../../legacy/server/lib/create_router/error_wrappers';
 
 import { TRANSFORM_STATE } from '../../../common/constants';
 import { TransformId } from '../../../common/types/transform';
@@ -54,7 +53,7 @@ import { RouteDependencies } from '../../types';
 
 import { addBasePath } from '../index';
 
-import { isRequestTimeout, fillResultsWithTimeouts, wrapError } from './error_utils';
+import { isRequestTimeout, fillResultsWithTimeouts, wrapError, wrapEsError } from './error_utils';
 import { registerTransformsAuditMessagesRoutes } from './transforms_audit_messages';
 import { IIndexPattern } from '../../../../../../src/plugins/data/common/index_patterns';
 
diff --git a/x-pack/plugins/transform/server/routes/api/transforms_audit_messages.ts b/x-pack/plugins/transform/server/routes/api/transforms_audit_messages.ts
index f01b2bdb73fd5..20cb6ffb4978b 100644
--- a/x-pack/plugins/transform/server/routes/api/transforms_audit_messages.ts
+++ b/x-pack/plugins/transform/server/routes/api/transforms_audit_messages.ts
@@ -6,13 +6,12 @@
 
 import { transformIdParamSchema, TransformIdParamSchema } from '../../../common/api_schemas/common';
 import { AuditMessage, TransformMessage } from '../../../common/types/messages';
-import { wrapEsError } from '../../../../../legacy/server/lib/create_router/error_wrappers';
 
 import { RouteDependencies } from '../../types';
 
 import { addBasePath } from '../index';
 
-import { wrapError } from './error_utils';
+import { wrapError, wrapEsError } from './error_utils';
 
 const ML_DF_NOTIFICATION_INDEX_PATTERN = '.transform-notifications-read';
 const SIZE = 500;
diff --git a/x-pack/plugins/translations/translations/ja-JP.json b/x-pack/plugins/translations/translations/ja-JP.json
index 8cf943fe02a1c..0ff132282034f 100644
--- a/x-pack/plugins/translations/translations/ja-JP.json
+++ b/x-pack/plugins/translations/translations/ja-JP.json
@@ -16693,9 +16693,6 @@
     "xpack.securitySolution.zeek.sfDescription": "通常のSYN/FIN完了",
     "xpack.securitySolution.zeek.shDescription": "接続元がFINに続きSYNを送信しました。レスポンダーからSYN-ACKはありません",
     "xpack.securitySolution.zeek.shrDescription": "レスポンダーがFINに続きSYNを送信しました。接続元からSYN-ACKはありません",
-    "xpack.server.checkLicense.errorExpiredMessage": "{licenseType} ライセンスが期限切れのため {pluginName} を使用できません",
-    "xpack.server.checkLicense.errorUnavailableMessage": "現在ライセンス情報が利用できないため {pluginName} を使用できません。",
-    "xpack.server.checkLicense.errorUnsupportedMessage": "ご使用の {licenseType} ライセンスは {pluginName} をサポートしていません。ライセンスをアップグレードしてください。",
     "xpack.snapshotRestore.addPolicy.breadcrumbTitle": "ポリシーを追加",
     "xpack.snapshotRestore.addPolicy.loadingIndicesDescription": "利用可能なインデックスを読み込み中…",
     "xpack.snapshotRestore.addPolicy.LoadingIndicesErrorMessage": "利用可能なインデックスを読み込み中にエラーが発生",
diff --git a/x-pack/plugins/translations/translations/zh-CN.json b/x-pack/plugins/translations/translations/zh-CN.json
index f1269822422bb..683cbdbb6bc8b 100644
--- a/x-pack/plugins/translations/translations/zh-CN.json
+++ b/x-pack/plugins/translations/translations/zh-CN.json
@@ -16703,9 +16703,6 @@
     "xpack.securitySolution.zeek.sfDescription": "正常 SYN/FIN 完成",
     "xpack.securitySolution.zeek.shDescription": "发起方已发送 SYN，后跟 FIN，响应方未发送 SYN ACK",
     "xpack.securitySolution.zeek.shrDescription": "响应方已发送 SYN ACK，后跟 FIN，发起方未发送 SYN",
-    "xpack.server.checkLicense.errorExpiredMessage": "您不能使用 {pluginName}，因为您的{licenseType}许可证已过期",
-    "xpack.server.checkLicense.errorUnavailableMessage": "您不能使用 {pluginName}，因为许可证信息当前不可用。",
-    "xpack.server.checkLicense.errorUnsupportedMessage": "您的{licenseType}许可证不支持 {pluginName}。请升级您的许可证。",
     "xpack.snapshotRestore.addPolicy.breadcrumbTitle": "添加策略",
     "xpack.snapshotRestore.addPolicy.loadingIndicesDescription": "正在加载可用索引……",
     "xpack.snapshotRestore.addPolicy.LoadingIndicesErrorMessage": "加载可用索引时出错",
diff --git a/x-pack/plugins/watcher/common/constants/plugin.ts b/x-pack/plugins/watcher/common/constants/plugin.ts
index f89ef95e9261f..fa95b86c0673b 100644
--- a/x-pack/plugins/watcher/common/constants/plugin.ts
+++ b/x-pack/plugins/watcher/common/constants/plugin.ts
@@ -4,11 +4,11 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { LICENSE_TYPE_GOLD, LicenseType } from '../../../../legacy/common/constants';
+import { LicenseType } from '../../../licensing/common/types';
 
 export const PLUGIN = {
   ID: 'watcher',
-  MINIMUM_LICENSE_REQUIRED: LICENSE_TYPE_GOLD as LicenseType,
+  MINIMUM_LICENSE_REQUIRED: 'gold' as LicenseType,
   getI18nName: (i18n: any): string => {
     return i18n.translate('xpack.watcher.appName', {
       defaultMessage: 'Watcher',
diff --git a/x-pack/plugins/watcher/server/types.ts b/x-pack/plugins/watcher/server/types.ts
index 167dcb3ab64c3..5ef3aef7de1c6 100644
--- a/x-pack/plugins/watcher/server/types.ts
+++ b/x-pack/plugins/watcher/server/types.ts
@@ -8,8 +8,6 @@ import { IRouter } from 'kibana/server';
 import { PluginSetupContract as FeaturesPluginSetup } from '../../features/server';
 import { LicensingPluginSetup } from '../../licensing/server';
 
-import { XPackMainPlugin } from '../../../legacy/plugins/xpack_main/server/xpack_main';
-
 export interface Dependencies {
   licensing: LicensingPluginSetup;
   features: FeaturesPluginSetup;
@@ -18,7 +16,6 @@ export interface Dependencies {
 export interface ServerShim {
   route: any;
   plugins: {
-    xpack_main: XPackMainPlugin;
     watcher: any;
   };
 }
diff --git a/x-pack/legacy/common/eui_styled_components/eui_styled_components.tsx b/x-pack/plugins/xpack_legacy/common/eui_styled_components.tsx
similarity index 100%
rename from x-pack/legacy/common/eui_styled_components/eui_styled_components.tsx
rename to x-pack/plugins/xpack_legacy/common/eui_styled_components.tsx
diff --git a/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/index.js b/x-pack/plugins/xpack_legacy/common/index.ts
similarity index 83%
rename from x-pack/legacy/plugins/xpack_main/server/routes/api/v1/index.js
rename to x-pack/plugins/xpack_legacy/common/index.ts
index 80baf7bf1a64d..8c0dace27faf4 100644
--- a/x-pack/legacy/plugins/xpack_main/server/routes/api/v1/index.js
+++ b/x-pack/plugins/xpack_legacy/common/index.ts
@@ -4,4 +4,4 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-export { xpackInfoRoute } from './xpack_info';
+export * from './eui_styled_components';
diff --git a/x-pack/tasks/build.ts b/x-pack/tasks/build.ts
index 41bf9587cad1e..a3b08a16f4b08 100644
--- a/x-pack/tasks/build.ts
+++ b/x-pack/tasks/build.ts
@@ -61,9 +61,6 @@ async function copySourceAndBabelify() {
         'plugins/**/*',
         'plugins/reporting/.phantom/*',
         'plugins/reporting/.chromium/*',
-        'legacy/common/**/*',
-        'legacy/plugins/**/*',
-        'legacy/server/**/*',
         'typings/**/*',
       ],
       {
diff --git a/x-pack/tasks/helpers/flags.ts b/x-pack/tasks/helpers/flags.ts
index 33ee126c2a2ee..8820a4d60aa40 100644
--- a/x-pack/tasks/helpers/flags.ts
+++ b/x-pack/tasks/helpers/flags.ts
@@ -4,14 +4,8 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { resolve } from 'path';
-
 import log from 'fancy-log';
 import getopts from 'getopts';
-import { toArray } from 'rxjs/operators';
-
-// @ts-ignore complicated module doesn't have types yet
-import { findPluginSpecs } from '../../../src/legacy/plugin_discovery';
 
 /*
   Usage:
@@ -53,18 +47,3 @@ export const FLAGS = {
         .map((id) => id.trim())
     : undefined,
 };
-
-export async function getEnabledPlugins() {
-  if (FLAGS.plugins) {
-    return FLAGS.plugins;
-  }
-
-  const { spec$ } = findPluginSpecs({
-    plugins: {
-      paths: [resolve(__dirname, '..', '..')],
-    },
-  });
-
-  const enabledPlugins: Array<{ getId: () => string }> = await spec$.pipe(toArray()).toPromise();
-  return enabledPlugins.map((spec) => spec.getId());
-}
diff --git a/x-pack/tsconfig.json b/x-pack/tsconfig.json
index 44c8449dc5dd0..7978a89231566 100644
--- a/x-pack/tsconfig.json
+++ b/x-pack/tsconfig.json
@@ -3,9 +3,6 @@
   "include": [
     "mocks.ts",
     "typings/**/*",
-    "legacy/common/**/*",
-    "legacy/server/**/*",
-    "legacy/plugins/**/*",
     "plugins/**/*",
     "test_utils/**/*",
     "tasks/**/*"
@@ -21,7 +18,6 @@
     "paths": {
       "kibana/public": ["src/core/public"],
       "kibana/server": ["src/core/server"],
-      "plugins/xpack_main/*": ["x-pack/legacy/plugins/xpack_main/public/*"],
       "test_utils/*": ["x-pack/test_utils/*"],
       "fixtures/*": ["src/fixtures/*"]
     },
diff --git a/x-pack/typings/hapi.d.ts b/x-pack/typings/hapi.d.ts
index 253b639a52ff2..dd9e0239aeee7 100644
--- a/x-pack/typings/hapi.d.ts
+++ b/x-pack/typings/hapi.d.ts
@@ -6,7 +6,6 @@
 
 import 'hapi';
 
-import { XPackMainPlugin } from '../legacy/plugins/xpack_main/server/xpack_main';
 import { ActionsPlugin, ActionsClient } from '../plugins/actions/server';
 import { AlertingPlugin, AlertsClient } from '../plugins/alerts/server';
 import { TaskManager } from '../plugins/task_manager/server';
@@ -17,7 +16,6 @@ declare module 'hapi' {
     getAlertsClient?: () => AlertsClient;
   }
   interface PluginProperties {
-    xpack_main: XPackMainPlugin;
     actions?: ActionsPlugin;
     alerts?: AlertingPlugin;
     task_manager?: TaskManager;