The 216604-6 is a 12-position, dual-row, right-angle through-hole receptacle from the AMPMODU HV 190 series. The gold mating finish (31.5 µinch over phosphor bronze) gives this connector a solid 500-plus mating cycle life in moderate-duty board-to-board interconnects. For a production run where the boards are mated once at assembly, that is overkill — but it also handles field-replaceable modules where the connector sees a few dozen cycles over the product life. The 0.126" solder-tail length is a standard through-hole length for 1.6 mm boards.
The row spacing is also 0.100", so the pinout is a 2×6 grid on a 2.54 mm pitch in both axes.