Sync with #66543

lib/compat/wordpress-6.7/rest-api.php

@@ -50,6 +50,39 @@ function gutenberg_block_editor_preload_paths_6_7( $paths, $context ) {
 		}
 	}
 
+	// Preload theme and global styles paths.
+	$excluded_paths = array();
+	if ( 'core/edit-site' === $context->name || 'core/edit-post' === $context->name ) {
+		$active_theme     = get_stylesheet();
+		$global_styles_id = WP_Theme_JSON_Resolver_Gutenberg::get_user_global_styles_post_id();
+		$paths[]          = array( '/wp/v2/global-styles/' . $global_styles_id, 'OPTIONS' );
+		$paths[]          = '/wp/v2/global-styles/themes/' . $active_theme . '?context=view';
+		$paths[]          = '/wp/v2/global-styles/themes/' . $active_theme . '/variations?context=view';
+
+		// Remove duplicate or unnecessary global styles paths.
+		$excluded_paths[] = '/wp/v2/global-styles/themes/' . $active_theme;
+		$excluded_paths[] = '/wp/v2/global-styles/' . $global_styles_id;
+		// Removes the edit context path originating Core's preload paths.
+		$excluded_paths[] = '/wp/v2/global-styles/' . $global_styles_id . '?context=view';
+		// Removes the edit context path originating from gutenberg_block_editor_preload_paths_6_6().
+		$excluded_paths[] = '/wp/v2/global-styles/' . $global_styles_id . '?context=edit';
+
+		// Remove excluded paths so they are not preloaded.
+		foreach ( $paths as $key => $path ) {
+			if ( in_array( $path, $excluded_paths, true ) ) {
+				unset( $paths[ $key ] );
+			}
+		}
+
+		/*
+		 * Add the global styles path with the correct context based on user caps.
+		 * The corresponding paths are removed above so their output is not rendered into the HTML
+		 * unnecessarily.
+		 */
+		$context = current_user_can( 'edit_theme_options' ) ? 'edit' : 'view';
+		$paths[] = "/wp/v2/global-styles/$global_styles_id?context=$context";
+	}
+
 	return $paths;
 }
 add_filter( 'block_editor_rest_api_preload_paths', 'gutenberg_block_editor_preload_paths_6_7', 10, 2 );

lib/load.php

@@ -47,7 +47,6 @@ function gutenberg_is_experiment_enabled( $name ) {
 	require __DIR__ . '/compat/wordpress-6.7/rest-api.php';
 
 	// WordPress 6.8 compat.
-	require __DIR__ . '/compat/wordpress-6.8/preload.php';
 	require __DIR__ . '/compat/wordpress-6.8/block-comments.php';
 	require __DIR__ . '/compat/wordpress-6.8/class-gutenberg-rest-comment-controller-6-8.php';