See ConfiguringPCISyncClock32Dev? for discussion of this topic.
From ntp-4.2.0 to ntp-4.2.2, more precisely with changeset 1.1152.9.9,
the refclock_gpsvme.c changed from a reference clock driver for a True
Time GPS-VME to a reference clock driver for a Brandywine Communications PCI-SyncClock32.