anchor.diff:    etcdctl = etcd; # added 2018-04-25
     exfat-utils = exfat;                  # 2015-09-11
     facette = throw "facette has been removed."; # added 2020-01-06
  +  fast-neural-doodle = throw "fast-neural-doodle has been removed, as the upstream project has been abandoned"; # added 2020-03-28
     fetchFromGithub = throw "You meant fetchFromGitHub, with a capital H.";
     ffadoFull = ffado; # added 2018-05-01
     firefox-esr-wrapper = firefox-esr;  # 2016-01
  
positive.code:   networkmanager_openconnect = networkmanager-openconnect; # added 2018-02-25
    networkmanager_openvpn = networkmanager-openvpn; # added 2018-02-25
    networkmanager_vpnc = networkmanager-vpnc; # added 2018-02-25
    nix-review = nixpkgs-review; # added 2019-12-22
    nfsUtils = nfs-utils;  # added 2014-12-06
    nginxUnstable = nginxMainline; # added 2018-04-25
    nilfs_utils = nilfs-utils; # added 2018-04-25
    nmap_graphical = nmap-graphical;  # added 2017-01-19
    nologin = shadow; # added 2018-04-25
    nxproxy = nx-libs; # added 2019-02-15
  
negative.code:   links = links2; # added 2016-01-31
    linux_rpi0 = linux_rpi1;
    linuxPackages_rpi0 = linuxPackages_rpi1;
    loadcaffe = throw "loadcaffe has been removed, as the upstream project has been abandoned"; # added 2020-03-28
    lttngTools = lttng-tools;  # added 2014-07-31
    lttngUst = lttng-ust;  # added 2014-07-31
    lua5_1_sockets = lua51Packages.luasocket; # added 2017-05-02
  