this derivation will be built:
  /nix/store/8mwczbzii2ix0l21igacpj7kc85cgk27-treefmt.toml.drv
this path will be fetched (5.7 MiB download, 27.9 MiB unpacked):
  /nix/store/rr2gszl86cb8kxdd7nwlr4nlj7197r2v-nickel-1.18.0