code: public static final String getIndexFileName() {
          Configuration config = ConfigUtils.getCurrentConfig();
          if (config != null) {
              return config.getString(INDEX_FILE_NAME_CONFIG_KEY, DEFAULT_INDEX_FILE_NAME);
          } else {
              return DEFAULT_INDEX_FILE_NAME;
          }
      }
docs: Returns the name of a page's index file, or {@link #DEFAULT_INDEX_FILE_NAME} if not in configuration.