Basic sync should be working, it's sometimes buggy though. Best is to try it yourself if you have a Fallout game. The current way of syncing is using the script engine to play the movement animations and to apply the heading angles on the NPCs. It's very simple and therefore not very efficient and leads to asyncs quite often (what we need is kind of interpolation, in general, more coordinated movement syncing - ATM it's like simply applying animations and angles, and if a player gets out-of-sync -> position hard reset).
https://github.com/Foxtacles/vaultmp/blob/master/Game.h
This is the top layer to control things in-game. There is a Interface thread which is concurrently querying the game through the API for updated data, as well as executing the input from the Game layer. In the end, it boils down to the script functions like GetPos, SetPos, etc. (most of it).
There is so much to be done :D I will compile a more detailed list soon.