core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.php b/core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.php
index b69d98a..9e8c0af 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ActiveLinkResponseFilter.php
@@ -232,6 +232,7 @@ public static function setLinkActiveClass($html_markup, $current_path, $is_front
    * {@inheritdoc}
    */
   public static function getSubscribedEvents() {
+    // Should run after any other response subscriber that modifies the markup.
     $events[KernelEvents::RESPONSE][] = ['onResponse', -512];
 
     return $events;