The Mutter window manager can function as standalone window manager application for GNOME-like desktops, and serves as the primary window manager for the GNOME Shell desktop, which is an integral part of GNOME 3. Mutter is extensible with plugins and supports numerous visual effects. GNOME Shell is written as a plugin to Mutter. Gala, a core component of the Pantheon desktop environment, is built using libmutter. budgie-wm, the window manager used in the Budgie desktop environment, is another window manager built on libmutter.