these 2 derivations will be built:
  /nix/store/v8a0vyxd55zg9hsdh13xk2qym5z9jsmp-flake-fmt-1.0.0.drv
  /nix/store/1142h07jy26034qnbw43h1rmyl05i08a-merge-when-green-0.3.0.drv