It's using smart summon, where a person, who can see the car because it's short range, uses their phone to move the car. They can stop it using their phone at any time by removing their finger from the touchscreen, yet weirdly didn't.
It's not autopilot, and it's not FSD, and it maxes out at 6 mph.
Also they've never updated the code for it, so it's not representative of the current tech in FSD