{self, ...}: {
  flake.overlays.default = _final: prev: {
    fairfax = prev.callPackage ./derivations/fairfax.nix {};
    river-bedload = prev.callPackage ./derivations/river-bedload {};
    nicotine-plus = prev.symlinkJoin {
      name = "nicotine";
      paths = [prev.nicotine-plus];
      nativeBuildInputs = [prev.makeWrapper];
      postBuild = ''
        wrapProgram $out/bin/nicotine \
          --set-default NICOTINE_LIBADWAITA 1
      '';
    };
    rose-pine-gtk-theme = prev.rose-pine-gtk-theme.overrideAttrs (_prevAttrs: {
      version = "master";
      src = prev.fetchFromGitHub {
        owner = "rose-pine";
        repo = "gtk";
        rev = "master";
        hash = "sha256-vCWs+TOVURl18EdbJr5QAHfB+JX9lYJ3TPO6IklKeFE=";
      };
    });
  };
  perSystem = {pkgs, ...}: {
    packages = self.overlays.default null pkgs;
  };
}