code: private LocaleID parseIdentity(String code, JsonObject root) throws IOException {
      JsonObject node = resolve(root, "main", code, "identity");
      return new LocaleID(
          string(node, "language"),
          string(node, "script"),
          string(node, "territory"),
          string(node, "variant"));
    }
docs: Parse the locale identity header from a calendar JSON tree.