anchor.diff:        default = "";
         example = "nostalgia";
         description = "Set this value to change the default skin used by MediaWiki.";
  +    };
  +
  +    skins = mkOption {
  +      default = [];
  +      type = types.listOf types.path;
  +      description =
  +        ''
  +          List of paths whose content is copied to the ‘skins’
  +          subdirectory of the MediaWiki installation.
  +        '';
       };
   
       extraConfig = mkOption {
  
positive.code:       sha256 = "1d8afbdh3lsg54b69mnh6a47psb3lg978xpp277qs08yz15cjf7q";
      };
  
      skinTarball = if config.defaultSkin == "clean" then src_clean_skin
               else if config.defaultSkin == "nixos" then src_nixos_skin
               else "";
  
      buildPhase = "
        if [ '${skinTarball}' ]; then
           tar xfz ${skinTarball} -C skins/;
        fi
      ";
  
      installPhase =
        ''
  
negative.code: with pkgs.lib;
  
  let
  
    mediawikiConfig = pkgs.writeText "LocalSettings.php"
      ''
  