Oh cool It stores:
a) position in 3 Vectors (x,y,z)
b) velocity (a,b,c)
So that’s it. 7 parts to this. But that’s all you need.
Position is stored in the unit of Mpc/h as double precision 3 vectors. Velocity is stored in peculiar velocity km/s as single precision 3 vectors. ID is stored as 8 bit unsigned integers