these 3 derivations will be built:
  /nix/store/b6rv4yryffmvlncw3daabwgcah1m45lk-Caddyfile.drv
  /nix/store/ms2axdfrb1fxblqrij4ndh0x6i38knd8-Caddyfile-formatted.drv
  /nix/store/a7h4k8f1fmsxdrv9kbzw0c4np1zz3cvx-james-caddy-source-test.drv