Symbol: MOUSE_EXPLORER_BUTTON4DOWN
sys/dev/atkbdc/psm.c
5002
(pb->ipacket[3] & MOUSE_EXPLORER_BUTTON4DOWN) ?
usr.sbin/moused/msconvd/msconvd.c
1646
act->button |= (pBuf[3] & MOUSE_EXPLORER_BUTTON4DOWN)