https://github.com/sanzoghenzo/my-pcs/tree/33c7e3b/pkgs (https://discourse.nixos.org/t/right-way-to-install-kodi-and-plugins/19181/36 https://github.com/NixOS/nixpkgs/blob/d7d18819bb70a1efe951dfa1eac9eebc01748c25/pkgs/top-level/kodi-packages.nix#L48)
the gimp.gtk attribute from passthru is used by plug-ins (https://discourse.nixos.org/t/solved-overriding-gimp-attributes-and-a-dependent-package/51003/4)
another example https://github.com/NixOS/nixpkgs/blob/086b448a5d54fd117f4dc2dee55c9f0ff461bdc1/pkgs/development/libraries/ffmpeg/generic.nix#L35
https://discourse.nixos.org/t/right-way-to-install-kodi-and-plugins/19181/35