diff --git a/.npmignore b/.npmignore
deleted file mode 100644
index 16c5705578..0000000000
--- a/.npmignore
+++ /dev/null
@@ -1,2 +0,0 @@
-css-to-ts.js
-tsconfig.json
diff --git a/package.json b/package.json
index e8e91e9bee..fbff5c2828 100644
--- a/package.json
+++ b/package.json
@@ -21,6 +21,16 @@
     "prebuild:ts": "find . -name '*.css' -type f | xargs node css-to-ts.js",
     "build:ts": "tsc"
   },
+  "files": [
+    "**/*.js",
+    "**/*.js.map",
+    "**/*.d.ts",
+    "**/*.scss",
+    "!css-to-ts.js",
+    "!**/test/**",
+    "!**/testing/**",
+    "!**/*_test.*"
+  ],
   "dependencies": {
     "lit": "^2.3.0",
     "tslib": "^2.4.0"
diff --git a/tsconfig.json b/tsconfig.json
index 346cc84a7e..99fcf43e14 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -3,7 +3,7 @@
     "allowUnreachableCode": false,
     "baseUrl": ".",
     "declaration": true,
-    "declarationMap": true,
+    "declarationMap": false,
     "downlevelIteration": true,
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
@@ -22,6 +22,7 @@
     },
     "skipLibCheck": true,
     "sourceMap": true,
+    "inlineSources": true,
     "strict": true,
     "strictNullChecks": false,
     "target": "es2020"