HM-DR10000EK D-VHS VCR: unmarked hidden sockets?
 

Does anyone know the purpose of this hidden socket on the rear of the HM-DR10000EK D-VHS VCR?

There are actually two of these sockets, both hidden by a tiny plastic sheet. They appear to be wired, but I cannot find any obvious reference to them in the service manual.

As they are adjacent to the Firewire connector, I am wondering whether these are for another digital output? Or perhaps they are for a non-European connection like a Japanese D-Terminal?

That certainly isn't D-Terminal. Its likely a diagnostic or factory testing port of some sort.

Remember D-VHS tech was never fleshed out. That may have been DOA feature that never saw fruition. We've seen that on other devices in the past, be it video or not. The DataVideo TBC-1000 has something like this, odd holes for nothing. A few have ports that seemingly do nothing. No manual documentation at all.