code: static public function configureScaffoldFormConfig(FormConfig $scaffold) {
          return $scaffold
              ->addTab($scaffold->translate(null, 'tab.general'), [
                  static::DEFAULT_BROWSER_TITLE,
                  static::BROWSER_TITLE_ADDITION,
              ])
              ->addTab($scaffold->translate(null, 'tab.localization'), [
                  static::LANGUAGES => KeyValueSetFormInput::create()
                      ->setMinValuesCount(1)
                      ->setAddRowButtonLabel($scaffold->translate(null, 'input.languages_add'))
                      ->setDeleteRowButtonLabel($scaffold->translate(null, 'input.languages_delete')),
                  static::DEFAULT_LANGUAGE => FormInput::create()
                      ->setType(FormInput::TYPE_SELECT)
                      ->setOptions(function () {
                          return static::languages();
                      }),
                  static::FALLBACK_LANGUAGES => KeyValueSetFormInput::create()
                      ->setAddRowButtonLabel($scaffold->translate(null, 'input.fallback_languages_add'))
                      ->setDeleteRowButtonLabel($scaffold->translate(null, 'input.fallback_languages_delete')),
              ]);
      }
docs: Get form inputs for app settings (used in CmfSettingsScaffoldConfig)
  You can use setting name as form input - it will be simple text input;
  In order to make non-text input - use instance of FormInput class or its descendants as value and
  setting name as key;
  @param FormConfig $scaffold
  @return FormConfig