this derivation will be built:
  /nix/store/55z3sjvs05idphqmx9xcz7z35smgdqh3-Blackbird-2017-12-13.drv
this path will be fetched (88.5 KiB download, 330.1 KiB unpacked):
  /nix/store/zd047xfdidz6jk7ww1r1bv41qcp8zkn7-gtk-engine-murrine-0.98.2