these 2 derivations will be built:
  /nix/store/4v04n3qjr22jy0yz4x7nfv1f9hcwy7q0-iets-0.1.0.drv
  /nix/store/lkr2z1sd5bbgvrbi5b7x3d61ic5n3f1g-iets-diff-e2e.drv