anchor.diff:        (mkIf cfg.memtest86.enable {
           "efi/memtest86/BOOTX64.efi" = "${pkgs.memtest86-efi}/BOOTX64.efi";
         })
  +      (mkIf cfg.netbootxyz.enable {
  +        "efi/netbootxyz/netboot.xyz.efi" = "${pkgs.netbootxyz-efi}";
  +      })
       ];
   
       boot.loader.systemd-boot.extraEntries = mkMerge [
  
positive.code:           efi    /efi/memtest86/BOOTX64.efi
          '';
        })
      ];
  
      system = {
  
negative.code: 
        entryFilename = mkOption {
          default = "memtest86.conf";
          type = types.str;
          description = ''
            <literal>systemd-boot</literal> orders the menu entries by the config file names,
            so if you want something to appear after all the NixOS entries,
            it should start with <filename>o</filename> or onwards.
          '';
        };
      };
  
      netbootxyz = {
        enable = mkOption {
          default = false;
          type = types.bool;
          description = ''
            Make <literal>netboot.xyz</literal> available from the
            <literal>systemd-boot</literal> menu. <literal>netboot.xyz</literal>
            is a menu system that allows you to boot OS installers and
            utilities over the network.
          '';
        };
  
        entryFilename = mkOption {
          default = "o_netbootxyz.conf";
          type = types.str;
          description = ''
            <literal>systemd-boot</literal> orders the menu entries by the config file names,
  