anchor.diff:    buildPerlPackage = perlPackages.buildPerlPackage; # added 2018-10-12
     buildGo112Package = throw "buildGo112Package has been removed"; # added 2020-04-26
     buildGo112Module = throw "buildGo112Module has been removed"; # added 2020-04-26
  -  buildkite-agent2 = throw "buildkite-agent2 has been discontinued. Please use buildkite-agent (v3.x)"; # added 2018-09-26
     buildkite-agent3 = buildkite-agent; # added 2018-09-26
     bundler_HEAD = bundler; # added 2015-11-15
     calibre-py2 = throw "calibre-py2 has been removed from nixpkgs, as calibre has upgraded to python 3. Please use calibre as replacement."; # added 2021-01-13
  
positive.code:     fontconfig 2.10.x hasn't had a release in years, is vulnerable to CVE-2016-5384
      and has only been used for old fontconfig caches.
    '';
    font-droid = throw "font-droid has been deprecated by noto-fonts"; # 2019-04-12
    foomatic_filters = foomatic-filters;  # 2016-08
    fsharp41 = throw "fsharp41 has been removed, please use dotnet-sdk_5 or later";
    fuse_exfat = exfat;                   # 2015-09-11
    fuseki = apache-jena-fuseki; # added 2018-04-25
    fusesmb = throw "fusesmb is abandoned by upstream"; # added 2019-10-15
    fwupdate = throw "fwupdate was merged into fwupd"; # added 2020-05-19
    g4py = python3Packages.geant4; # added 2020-06-06
    gccApple = throw "gccApple is no longer supported"; # added 2018-04-25
    gdal_1_11 = throw "gdal_1_11 was removed. Use gdal instead."; # added 2021-04-03
    gdb-multitarget = gdb; # added 2017-11-13
    gdk_pixbuf = gdk-pixbuf; # added 2019-05-22
  
negative.code:   wicd = throw "wicd has been removed as it is abandoned."; # added 2021-09-11
    wineStaging = wine-staging; # added 2018-01-08
    winusb = woeusb; # added 2017-12-22
    winswitch = throw "winswitch has been removed from nixpkgs."; # added 2019-12-10
    wireshark-gtk = throw "wireshark-gtk is not supported anymore. Use wireshark-qt or wireshark-cli instead."; # added 2019-11-18
    wireguard = wireguard-tools; # added 2018-05-19
  