anchor.diff:          example = [ "nixos" ];
           description = ''
             IRC channels to join.
  +        '';
  +      };
  +
  +      hasBitlbeeControlChannel = mkOption {
  +        type = types.bool;
  +        default = false;
  +        description = ''
  +          Whether to add the special Bitlbee operations channel.
  +        '';
  +      };
  +
  +      extraConf = mkOption {
  +        default = "";
  +        type = types.lines;
  +        example = ''
  +          Encoding = ^UTF-8
  +          FloodBurst = 4
  +          FloodRate = 1.00
  +          IRCConnectEnabled = true
  +          Ident = johntron
  +          JoinDelay = 0
  +          Nick = johntron
  +        '';
  +        description = ''
  +          Extra config for the network.
           '';
         };
       };
  
positive.code:             ${ lib.concatStringsSep "\n" (lib.mapAttrsToList (name: net: ''
                <Network ${name}>
                    ${concatMapStrings (m: "LoadModule = ${m}\n") net.modules}
                    Server = ${net.server} ${if net.useSSL then "+" else ""}${toString net.port}
  
                    ${concatMapStrings (c: "<Chan #${c}>\n</Chan>\n") net.channels}
                </Network>
                '') confOpts.networks) }
      </User>
  
negative.code:           A list of global znc module packages to add to znc.
          '';
        };
  
        mutable = mkOption {
          default = false;
          type = types.bool;
          description = ''
            Indicates whether to allow the contents of the `dataDir` directory to be changed
            by the user at run-time.
            If true, modifications to the ZNC configuration after its initial creation are not
              overwritten by a NixOS system rebuild.
            If false, the ZNC configuration is rebuilt by every system rebuild.
            If the user wants to manage the ZNC service using the web admin interface, this value
              should be set to true.
          '';
        };
  
        extraFlags = mkOption {
          default = [ ];
          example = [ "--debug" ];
  