What is the purpose of the Audi A8's e-tron feature?

I have heard that the Audi A8 has an e-tron feature, but I am not sure what it is used for. Can someone kindly explain?

The Audi A8's e-tron feature is an electric drive system that helps improve fuel efficiency and reduce emissions. It also allows for smoother and quieter driving experience compared to traditional gasoline engines.

The e-tron feature in the Audi A8 provides additional power and torque to the vehicle, allowing for better performance and acceleration. It also offers regenerative braking, which helps to recharge the battery while driving.