How does the Audi A8 utilize hybrid technology?

I've heard that the Audi A8 is a hybrid vehicle, but I'm not sure what that means or how it works. Could you explain how the A8 uses hybrid technology?

The Audi A8 utilizes a mild-hybrid system that uses a small 48-volt lithium-ion battery to assist the engine and improve fuel efficiency. It also has regenerative braking, capturing energy to help power the car.

The A8 also has a start-stop function, which shuts off the engine when the car is at a complete stop to save more fuel. The hybrid technology helps the A8 achieve an impressive 27 mpg in combined city and highway driving.