How does the Audi A8's all-wheel steering work?

I've heard that some models of the Audi A8 have all-wheel steering, but I'm not sure how it works. Can someone explain the technical details behind it?

The Audi A8's all-wheel steering utilizes an electro-mechanical system that allows the rear wheels to turn up to 5 degrees in the opposite direction of the front wheels at low speeds, and up to 2.5 degrees in the same direction as the front wheels at higher speeds. This allows for improved maneuverability and stability in different driving situations.