diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php
index a72541a1ee..d3830e8785 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php
@@ -16,7 +16,13 @@
  * @see WP_REST_Controller
  */
 class WP_REST_Autosaves_Controller extends WP_REST_Revisions_Controller {
-
+	/**
+	 * The namespace of this controller's route.
+	 *
+	 * @since 5.0.0
+	 * @var string
+	 */
+	private $rest_namespace;
 	/**
 	 * Parent post type.
 	 *