anchor.diff:  let
     cfg = config.virtualisation.virtualbox.host;
   
  -  virtualbox = pkgs.virtualbox.override {
  +  virtualbox = cfg.package.override {
       inherit (cfg) enableExtensionPack enableHardening headless;
     };
   
  
positive.code:       '';
      };
  
      enableExtensionPack = mkEnableOption "VirtualBox extension pack";
  
      addNetworkInterface = mkOption {
        type = types.bool;
  
negative.code:         Automatically set up a vboxnet0 host-only network interface.
        '';
      };
  
      enableExtensionPack = mkEnableOption "VirtualBox extension pack";
  
      enableHardening = mkOption {
        type = types.bool;
  