diff --git a/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php b/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php
index c87ef63..41fe7ed 100644
--- a/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php
+++ b/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php
@@ -163,6 +163,8 @@ public function traceHandler() {
   }
 
   /**
+   * Returns the values stored in the active session and the user ID.
+   *
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   The request object.
    *