Plugin: Deprecate window._wpLoadGutenbergEditor (#13547)

docs/designers-developers/developers/backward-compatibility/deprecations.md

@@ -56,6 +56,7 @@ The Gutenberg project's deprecation policy is intended to support backward compa
 - The PHP function `gutenberg_meta_box_post_form_hidden_fields` has been removed. Use [`the_block_editor_meta_box_post_form_hidden_fields`](https://developer.wordpress.org/reference/functions/the_block_editor_meta_box_post_form_hidden_fields/) instead.
 - The PHP function `gutenberg_toggle_custom_fields` has been removed.
 - The PHP function `gutenberg_collect_meta_box_data` has been removed. Use [`register_and_do_post_meta_boxes`](https://developer.wordpress.org/reference/functions/register_and_do_post_meta_boxes/) instead.
+- `window._wpLoadGutenbergEditor` has been removed. Use `window._wpLoadBlockEditor` instead. Note: This is a private API, not intended for public use. It may be removed in the future.
 
 ## 4.5.0
 - `Dropdown.refresh()` has been deprecated as the contained `Popover` is now automatically refreshed.

lib/client-assets.php

@@ -1208,11 +1208,27 @@ function gutenberg_editor_scripts_and_styles( $hook ) {
 
 	$init_script = <<<JS
 	( function() {
-		window._wpLoadGutenbergEditor = window._wpLoadBlockEditor = new Promise( function( resolve ) {
+		window._wpLoadBlockEditor = new Promise( function( resolve ) {
 			wp.domReady( function() {
 				resolve( wp.editPost.initializeEditor( 'editor', "%s", %d, %s, %s ) );
 			} );
 		} );
+
+		Object.defineProperty( window, '_wpLoadGutenbergEditor', {
+			get: function() {
+				// TODO: Hello future maintainer. In removing this deprecation,
+				// ensure also to check whether `wp-editor`'s dependencies in
+				// `package-dependencies.php` still require `wp-deprecated`.
+				wp.deprecated( '`window._wpLoadGutenbergEditor`', {
+					plugin: 'Gutenberg',
+					version: '5.2',
+					alternative: '`window._wpLoadBlockEditor`',
+					hint: 'This is a private API, not intended for public use. It may be removed in the future.'
+				} );
+
+				return window._wpLoadBlockEditor;
+			}
+		} );
 } )();
 JS;