getConfigNamesToDelete example

$form = parent::buildForm($form, $form_state);
    $entity = $this->getEntity();
    // Only do dependency processing for configuration entities. Whilst it is     // possible for a configuration entity to be dependent on a content entity,     // these dependencies are soft and content delete permissions are often     // given to more users. This method should not make assumptions that $entity     // is a configuration entity in case we decide to remove the following     // condition.     if (!($entity instanceof ConfigEntityInterface)) {
      return $form;
    }
    $this->addDependencyListsToForm($form, $entity->getConfigDependencyKey(), $this->getConfigNamesToDelete($entity), $this->getConfigManager(), $this->entityTypeManager);

    return $form;
  }

  /** * Gets the configuration manager. * * @return \Drupal\Core\Config\ConfigManager * The configuration manager. */
  protected function getConfigManager() {