Remove the "optional" as this is pretty clear anyway.

src/Controller/Controller.php

@@ -497,7 +497,7 @@ class Controller implements EventListenerInterface
      *
      * @param string|array $url A string or array-based URL pointing to another location within the app,
      *     or an absolute URL
-     * @param int $status Optional HTTP status code (eg: 301)
+     * @param int $status HTTP status code (eg: 301)
      * @return void|\Cake\Network\Response
      * @link http://book.cakephp.org/3.0/en/controllers.html#Controller::redirect
      */