anchor.diff:  { stdenv
   , lib
   , fetchFromGitHub
  +, wrapGAppsHook
  +, installShellFiles
   , python3
  -, wrapGAppsHook
   , gobject-introspection
   , gtk3
   , gdk-pixbuf
  +
   # Recommended Dependencies:
  -, unrarSupport ? false
  +, unrarSupport ? false  # unfree software
   , unrar
   , p7zip
   , lhasa
  
positive.code:     )
    '';
  
    # real pytests seem to be broken upstream
    checkPhase = ''
      $out/bin/comicthumb --help > /dev/null
      $out/bin/${pname} --help > /dev/null
  
negative.code:   pname = "mcomix3";
    version = "unstable-2020-11-23";
  
    # no official release on pypi/github and no build system
    src = fetchFromGitHub {
      repo   = "${pname}";
      owner  = "multiSnow";
  