gtk2/docs/reference/gdk/events.md

Title: Events

Handling events from the window system

In GTK applications the events are handled automatically by toplevel widgets and passed on to the event controllers of appropriate widgets, so using [class@Gdk.Event] and its related API is rarely needed.

[class@Gdk.Event] and its derived types are immutable data structures, created by GTK itself to represent windowing system events.