anchor.diff:        peek
         perlPackages.FileMimeInfo
         qalculate-gtk
  -      shared_mime_info
         termite
         unstable.kitty
       ];
  
positive.code: 
      # Desktop packages.
      systemPackages = with pkgs; [
        arandr
        arc-icon-theme
        arc-theme
  
negative.code:             };
            };
          };
  
        };
  
        # Disable Xterm.
  