.buildOrThrow();
    ImmutableSet<String> uppercaseAcronyms =
        ImmutableSet.of(
            "CH", "ID", "DNT", "DNS", "DPR", "ECT", "GPC", "HTTP2", "IP", "MD5", "P3P", "RTT", "TE",
            "UA", "UID", "URL", "WWW", "XSS");

    for (Field field : httpHeadersFields()) {
      assertEquals(
          upperToHttpHeaderName(field.getName(), specialCases, uppercaseAcronyms), field.get(null));

   * @since 31.0
   */
  public static final String ECT = "ECT";

  /**
   * The HTTP <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/RTT">{@code
   * RTT}</a> header field name.
   *
   * @since 31.0
   */
  public static final String RTT = "RTT";

  /**
   * The HTTP <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Save-Data">{@code
   * Save-Data}</a> header field name.
   *