_ckeditor5_get_langcode_mapping example

$plugin_config = $this->ckeditor5PluginManager->getCKEditor5PluginConfig($editor);

    $settings = [
      'toolbar' => [
        'items' => $toolbar_items,
        'shouldNotGroupWhenFull' => in_array('-', $toolbar_items, TRUE),
      ],
    ] + $plugin_config;

    if ($this->moduleHandler->moduleExists('locale')) {
      $language_interface = $this->languageManager->getCurrentLanguage();
      $settings['language']['ui'] = _ckeditor5_get_langcode_mapping($language_interface->getId());
    }

    return $settings;
  }

  /** * {@inheritdoc} */
  public function getLibraries(Editor $editor) {
    $plugin_libraries = $this->ckeditor5PluginManager->getEnabledLibraries($editor);