diff --git a/core/modules/system/lib/Drupal/system/EventSubscriber/AdminRouteSubscriber.php b/core/modules/system/lib/Drupal/system/EventSubscriber/AdminRouteSubscriber.php
index 501cdc9..ef70321 100644
--- a/core/modules/system/lib/Drupal/system/EventSubscriber/AdminRouteSubscriber.php
+++ b/core/modules/system/lib/Drupal/system/EventSubscriber/AdminRouteSubscriber.php
@@ -36,6 +36,7 @@ public static function getSubscribedEvents() {
     // Use a higher priority than \Drupal\field_ui\Routing\RouteSubscriber or
     // \Drupal\views\EventSubscriber\RouteSubscriber to ensure we add the
     // option to their routes.
+    // @todo https://drupal.org/node/2158571
     $events[RoutingEvents::ALTER] = array('onAlterRoutes', -200);
 
     return $events;