anchor.diff:              muc_room_default_change_subject = ${toLua muc.roomDefaultChangeSubject}
               muc_room_default_history_length = ${toLua muc.roomDefaultHistoryLength}
               muc_room_default_language = ${toLua muc.roomDefaultLanguage}
  -
  -          '') cfg.muc}
  +            ${ muc.extraConfig }
  +        '') cfg.muc}
   
         ${ lib.optionalString (cfg.uploadHttp != null) ''
           Component ${toLua cfg.uploadHttp.domain} "http_upload"
  
positive.code: 
        https_ports = ${toLua cfg.httpsPorts}
  
        ${lib.concatMapStrings (muc: ''
          Component ${toLua muc.domain} "muc"
              modules_enabled = { "muc_mam"; ${optionalString muc.vcard_muc ''"vcard_muc";'' } }
  
negative.code:         type = types.str;
          default = "en";
          description = "Default room language.";
        };
        extraConfig = mkOption {
          type = types.lines;
          default = "";
          description = "Additional MUC specific configuration";
        };
      };
    };
  