There are matching water port openings on the front ... and on the back of the block and the head. There is also an opening on the valve side midway on the block and head.
So why is there an opening midway on the inlet side of the head .... but no mating opening on the block?
I think the extra hole is necessary as part of the casting process. By the way the two banana shaped holes are not the same and there is a correct way to mount the head gasket.