nixpkgs/pkgs/misc/bleeding-edge-fetch-info/nix_repository_manager.nix

 args: with args; fetchurl { 
  url = http://mawercer.de/~nix/repos/nix_repository_manager.tar.gz;
  sha256 = "449065f8411c5628b9fe88445601558dfd9a5f87b1703df9465838ef0afb9d34";}