I think that where the impact happened leaving that dent and crack, and perhaps the missing part was propelled out under load. The black bit behind the crack at 4.30 o'clock is the bearing seal.
And I think all of the gold coloured metal is part of the hub body.
RIP hub? Keep riding and don't worry about it? Wheel spins straight, rotor spins straight, no play in axle, gears shift fine.