I'd take a picture of what you are talking about and post it here. MHR is 15 pin 5-5-5 VGA cable.

The only other thing in a 568 that is remotely like that is the RS232 port which is 9 pin D-Type (5-4 two row) connector and NOT MHR - it is used for connecting a computer for firmware and programming. IIRC 568.2mm had MHR and 568.2 doesn't

main room: 861v4, 2x6000L/R (24/96) 1x5500HC (24/96), 2x DSP33(Rears)
MS200/Roon, 598, Revox b710mkII tape deck, Revox b760 FM tuner, Revox b790 turntable
bedroom: 568.2mm, 3x5000(LCR) (24/96)