Source: modules/ckeditor/js/ckeditor.language.admin.es6.js

(function ($, Drupal) {
  /**
   * Provides the summary for the "language" plugin settings vertical tab.
   */
  Drupal.behaviors.ckeditorLanguageSettingsSummary = {
    attach() {
      $('#edit-editor-settings-plugins-language').drupalSetSummary((context) =>
        $(
          '#edit-editor-settings-plugins-language-language-list-type option:selected',
        ).text(),
      );
    },
  };
})(jQuery, Drupal);