this derivation will be built:
  /nix/store/aqzly53i98ks4mxy1rcl56bq82dlaygi-Blackbird-2017-12-13.drv
this path will be fetched (91.5 KiB download, 328.0 KiB unpacked):
  /nix/store/fxh9z260140dgkqcb9kyqlq0pxpmvyp8-gtk-engine-murrine-0.98.2