What are the odds there's a Prime universe Galaxy class with a lift-kit on their nacelles, rolling-coal venting-plasma, with an aftermarket aft tractor beam hauling 3 runabout shuttles, flying a Terra Prime flag, a silhouette window decal of Phillip Green giving the finger, and when he docks with a star base the captain constantly complains about the price of dilithium.
I think it's part of the universal translator. Based on commonalities in construction between post-warp species, they can tell which way is up usually. That's why the Borg and the Gorn are so scary. Their ships don't have an up
They're obviously not all on the same galactic plain at all times but it's be customary if 2 ships are to meet at a certain spot from different directions it'd be customary for them to adjust their pitch yaw and roll to match