@Override
  protected @NotNull List<T> buildExtensions(@NotNull String stringKey, @NotNull Language key) {
    List<MetaLanguage> metaLanguages = LanguageUtil.matchingMetaLanguages(key);
    if (metaLanguages.isEmpty()) {
      return super.buildExtensions(stringKey, key);
    }

    Set<String> allKeys = new HashSet<>(metaLanguages.size() + 1);
    allKeys.add(stringKey);
    for (MetaLanguage language : metaLanguages) {
      allKeys.add(keyToString(language));
    }
    return buildExtensions(allKeys);
  }
@Override
  protected @NotNull List<T> buildExtensions(@NotNull String stringKey, @NotNull Language key)