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 = "f85846540a88f0c168ab6632a6bcba20fa4a41e263f7183c354e8e913b2c7938";}