I think I've noticed something interesting with OP_ClientUpdate/playerSelfPosStruct packets.

When a packet contains movement data (as opposed to all delta values being 0), there are 2 extra bytes at the end of the packet, bringing its length to 44. When no movement is involved, the packet is 42 bytes long.

I figure the additional bytes are a CRC or something along those lines. I'm trying to make sense of it on my end, but I don't really know where to start.

Have any devs ever looked into this?