final: prev: {
  gnome = prev.gnome.overrideScope' (gnomeFinal: gnomePrev: {
    mutter = gnomePrev.mutter.overrideAttrs ( old: {
      src = prev.fetchgit {
        url = "https://gitlab.gnome.org/vanvugt/mutter.git";
        # GNOME 45: triple-buffering-v4-45
        rev = "0b896518b2028d9c4d6ea44806d093fd33793689";
        sha256 = "sha256-mzNy5GPlB2qkI2KEAErJQzO//uo8yO0kPQUwvGDwR4w=";
      };
    } );
  });
}