diff --git a/core/modules/language/language.admin.js b/core/modules/language/language.admin.js
index 7f59a86..cedd78d 100644
--- a/core/modules/language/language.admin.js
+++ b/core/modules/language/language.admin.js
@@ -11,6 +11,9 @@
    * Makes language negotiation inherit user interface negotiation.
    *
    * @type {Drupal~behavior}
+   *
+   * @prop {Drupal~behaviorAttach} attach
+   *   Attach behavior to language negotiation admin user interface.
    */
   Drupal.behaviors.negotiationLanguage = {
     attach: function () {