dropme! TB 42583: Modify moz-support-link for Tor Browser.

    const torManualPrefix = "tor-manual:";

    if (supportPage.startsWith(torManualPrefix)) {

      const torManualPage = supportPage.substring(torManualPrefix.length);

      this.href = `about:manual#${torManualPage}`;

      const [page, anchor] = torManualPage.split("_", 2);

      let locale = Services.locale.appLocaleAsBCP47;

      if (locale === "ja-JP-macos") {

        // Convert quirk-locale to the locale used for tor project.

        locale = "ja";

      }

      let href = `https://tb-manual.torproject.org/${locale}/${page}/`;

      if (anchor) {

        href = `${href}#${anchor}`;

      }

      this.href = href;

      return;

    }

    // For base-browser we sometimes want to override firefox support links with