Add REST API endpoints

src/wp-includes/class-wp-widget-factory.php

@@ -102,4 +102,22 @@ public function _register_widgets() {
 			$this->widgets[ $key ]->_register();
 		}
 	}
+
+	/**
+	 * Returns the registered WP_Widget object for the given widget type.
+	 *
+	 * @since 5.8.0
+	 *
+	 * @param string $id_base Widget type ID.
+	 * @return WP_Widget|null
+	 */
+	public function get_widget_object( $id_base ) {
+		foreach ( $this->widgets as $widget_object ) {
+			if ( $widget_object->id_base === $id_base ) {
+				return $widget_object;
+			}
+		}
+
+		return null;
+	}
 }

src/wp-includes/default-widgets.php

@@ -63,3 +63,6 @@
 
 /** WP_Widget_Custom_HTML class */
 require_once ABSPATH . WPINC . '/widgets/class-wp-widget-custom-html.php';
+
+/** WP_Widget_Block class */
+require_once ABSPATH . WPINC . '/widgets/class-wp-widget-block.php';

src/wp-includes/rest-api.php

@@ -313,6 +313,18 @@ function create_initial_rest_routes() {
 	$controller = new WP_REST_Plugins_Controller();
 	$controller->register_routes();
 
+	// Sidebars.
+	$controller = new WP_REST_Sidebars_Controller();
+	$controller->register_routes();
+
+	// Widget Types.
+	$controller = new WP_REST_Widget_Types_Controller();
+	$controller->register_routes();
+
+	// Widgets.
+	$controller = new WP_REST_Widgets_Controller();
+	$controller->register_routes();
+
 	// Block Directory.
 	$controller = new WP_REST_Block_Directory_Controller();
 	$controller->register_routes();