Reference

XMotionEvent(3x) on Linux

The text 52723944baad, as Debian 2.2 (Potato), Debian 2.1 (Slink), Debian 2.0 (Hamm), Debian 1.3 (Bo) shipped it.

KeyPress, KeyRelease, ButtonPress, ButtonRelease, and MotionNotify event structures

XMotionEvent(3x) on Linux now