Robot does not send the following key events, as tested on macOS 13.5.1 and Windows 11:

KP_DOWN
KP_LEFT,
KP_RIGHT,
KP_UP

To reproduce, run the attached program and notice no events being sent for KP_* key codes:

keycode=LEFT key.press=LEFT
keycode=KP_LEFT key.press=null
keycode=KP_RIGHT key.press=null
keycode=KP_DOWN key.press=null
keycode=KP_UP key.press=null
keycode=RIGHT key.press=RIGHT
keycode=DOWN key.press=DOWN
keycode=UP key.press=UP

(was found while writing behavior tests for JDK-8314906)