Describes the kind of window.
root window; this window has no parent, covers the entire screen, and is created by the window system
toplevel window (used to implement gtk.Window)
child window (used to implement e.g. gtk.Entry)
override redirect temporary window (used to implement gtk.Menu)
foreign window (see Window.foreignNew)
offscreen window (see [Offscreen Windows][OFFSCREEN-WINDOWS]). Since 2.18
subsurface-based window; This window is visually tied to a toplevel, and is moved/stacked with it. Currently this window type is only implemented in Wayland. Since 3.14