Looks like a standard EPS12V to me (except that the top-pins are not split as usual), since Server-GPUs are typically powered by EPS-connectors rather then PCIe-power-connectors.
But then again
irritates me a little since they should be the same size as ATX12V connectors, which IIRC are the same size as PCIe connectors…
Pinging @wendell since he worked with the Z90 variant.
In the review I cover they are standard ish connectors and supply 12v power for addin cards. So you can get a cable that goes from this small connector to regular 6/8 pin pcie connectors or eps12v connectors for e.g. Tesla v100 cards
I can check the pinout for you if you can find an 8 pin one for sale. It’s the same connector the 2019 Mac pro used (8 pin) for pcie devices (I think) which is a standard server form factor
I know it as mini eps12v but you need a slight wiring change from mini eps12v to pcie power. Maybe I should carry those on the l1 store