diff --git a/core/lib/Drupal/Core/Messenger/Messenger.php b/core/lib/Drupal/Core/Messenger/Messenger.php
index f94ace9903..454c269142 100644
--- a/core/lib/Drupal/Core/Messenger/Messenger.php
+++ b/core/lib/Drupal/Core/Messenger/Messenger.php
@@ -96,6 +96,7 @@ public function deleteAll() {
    * {@inheritdoc}
    */
   public function deleteByType($type) {
+    // Flash bag gets and clears flash messages from the stack.
     return $this->flashBag->get($type);
   }