The X Window system used in most versions of BSD is maintained by the <link xlink:href="http://www.X.org/">X.Org project</link>. FreeBSD allows the user to choose from a variety of desktop environments, such as <application>Gnome</application>, <application>KDE</application>, or <application>Xfce</application>; and lightweight window managers like <application>Openbox</application>, <application>Fluxbox</application>, or <application>Awesome</application>.