anchor.diff:  
       passthru.updateScript = xfce.updateScript {
         inherit pname version attrPath rev-prefix odd-unstable patchlevel-unstable;
  -      versionLister = xfce.gitLister src.url;
  +      versionLister = xfce.gitLister src.meta.homepage;
       };
   
       meta = with stdenv.lib; {
  -      homepage = "https://git.xfce.org/${category}/${pname}/about";
  +      homepage = "https://gitlab.xfce.org/${category}/${pname}/about";
         license = licenses.gpl2; # some libraries are under LGPLv2+
         platforms = platforms.linux;
       };
  
positive.code: { stdenv, fetchgit, pkgconfig, xfce4-dev-tools, hicolor-icon-theme, xfce, wrapGAppsHook }:
  
  { category
  , pname
  
negative.code:     buildInputs = [ hicolor-icon-theme ];
      configureFlags = [ "--enable-maintainer-mode" ];
  
      src = fetchFromGitLab {
        domain = "gitlab.xfce.org";
        owner = category;
        repo = pname;
        inherit rev sha256;
      };
  
  