anchor.diff:        let
           updateSource = gnome.updateScript {
             packageName = "librsvg";
  -          versionPolicy = "odd-unstable";
           };
   
           updateLockfile = {
  
positive.code: 
    src = fetchurl {
      url = "mirror://gnome/sources/${pname}/${lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
      sha256 = "bmJsVk41S82MOEuQ+OTzCzA6+mweDLXMVroUkAxdtzA=";
    };
  
    cargoDeps = rustPlatform.fetchCargoTarball {
      inherit src;
      name = "${pname}-${version}";
      hash = "sha256-tvfdRGyrEkEh6sb69f0ugfzR2bgGdWa05pSyovpXAF8=";
      # TODO: move this to fetchCargoTarball
      dontConfigure = true;
    };
  
negative.code: 
  stdenv.mkDerivation rec {
    pname = "librsvg";
    version = "2.55.1";
  
    outputs = [ "out" "dev" ] ++ lib.optionals withIntrospection [
      "devdoc"
  