xev
KeymapNotify event, serial 27, synthetic NO, window 0x0, keys: 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
That's pressing Ctrl+WWW (Special Fn key from my HP 530)
xev
KeymapNotify event, serial 27, synthetic NO, window 0x0,
keys: 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
That's pressing Ctrl+WWW (Special Fn key from my HP 530)