diff --git a/core/lib/Drupal/Core/Field/AllowedTagsXssTrait.php b/core/lib/Drupal/Core/Field/AllowedTagsXssTrait.php
index f7eafdf..4bc14e6 100644
--- a/core/lib/Drupal/Core/Field/AllowedTagsXssTrait.php
+++ b/core/lib/Drupal/Core/Field/AllowedTagsXssTrait.php
@@ -33,6 +33,7 @@
    *   valid UTF-8.
    */
   public function fieldFilterXss($string) {
+    // Keep safe designation from Drupal\Component\Utility\Xss::filter.
     return SafeMarkup::set(Html::normalize(Xss::filter($string, $this->allowedTags())));
   }