Issue #3298889: Make \Drupal\package_manager_test_api\ApiController more easily extendable

package_manager/tests/modules/package_manager_test_api/src/ApiController.php

@@ -17,6 +17,8 @@ use Symfony\Component\HttpFoundation\Request;
 class ApiController extends ControllerBase {
 
   /**
+   * The route to redirect to after the operation has been applied.
+   *
    * @var string
    */
   protected $finishedRoute = 'package_manager_test_api.finish';