{
  version = "56.0a1" + "-" + "20170717100212";
  sources = [
    { url = "http://archive.mozilla.org/pub/firefox/nightly/latest-mozilla-central/firefox-56.0a1.en-US.linux-x86_64.tar.bz2";
      locale = "en-US";
      arch = "linux-x86_64";
      sha512 = "389ada65229fa6225a918041f77eed26cff321d649b8e9206835364e967fe3312dba9f7de9fbea52daf934265b804de447dddee60932d5019f8361884c9f3bde";
    }
  ];
}