{
  version = "57.0a1" + "-" + "20170829";
  sources = [
    { url = "https://download-installer.cdn.mozilla.net/pub/firefox/nightly/latest-mozilla-central/firefox-57.0a1.en-US.linux-x86_64.tar.bz2";
      locale = "en-US";
      arch = "linux-x86_64";
      sha512 = "1ggz8rl7n6j6qx7sira5dmqfy769swxh0dpi4mn6fdc7ppbrbyz58g4a47f6g1ng04y646h75yxdhqjp55nxqcp7v861b004bzf9b88";
    }
  ];
}