child window (used to implement e.g. GtkEntry)
foreign window (see gdk_window_foreign_new())
offscreen window (see [Offscreen Windows][OFFSCREEN-WINDOWS]). Since 2.18
root window; this window has no parent, covers the entire screen, and is created by the window system
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
override redirect temporary window (used to implement
GtkMenu)
toplevel window (used to implement GtkWindow)
Describes the kind of window.