anchor.diff:        example = ''[ { port = "any"; proto = "any"; host = "any"; } ]'';
       };
   
  -    extraConfig = mkOption {
  -      type = types.attrs;
  +    settings = {
  +      type = format.type;
         default = {};
  -      description = "Extra configuration added to the Nebula config file.";
  +      description = ''
  +        Nebula configuration. Refer to
  +        <link xlink:href="https://github.com/slackhq/nebula/blob/master/examples/config.yml"/>
  +        for details on supported values.
  +      '';
         example = literalExample ''
           {
             lighthouse.dns = {
  
positive.code:           Restart = "always";
            User = serviceUser;
            Group = serviceGroup;
            ExecStart = "${cfg.package}/bin/nebula -config ${nebulaConfig}";
          };
        };
  
  
negative.code: 
    cfg = config.services.nebula;
    nebulaDesc = "Nebula VPN service";
  
    format = pkgs.formats.yaml {};
    configFile = format.generate "nebula-config.yml" cfg.settings;
  
  in
  {
  