DisplayManager.get
Gets the singleton [gdk.display_manager.DisplayManager] object.
When called for the first time, this function consults the GDK_BACKEND environment variable to find out which of the supported GDK backends to use (in case GDK has been compiled with multiple backends).
Applications can use funcset_allowed_backends to limit what backends will be used.
Returns
The global [gdk.display_manager.DisplayManager] singleton