these 2 derivations will be built:
  /nix/store/2csq5hk0ipwdngmyhc5vfig7j8wrs3jk-iets-0.1.0.drv
  /nix/store/6q0qw5ah4r0b4wl3hwqnb8as9al5ra8c-iets-diff-e2e.drv