What is regeneration braking and how does it work in the Audi e-Tron?

I've heard that the Audi e-Tron has a feature called regeneration braking. Can you explain how this works and how it benefits the car's performance and efficiency?

Regeneration braking is a clever technology that allows the car to recover energy lost while braking. This energy is then stored in the car's battery for later use. This not only improves the car's efficiency, but also provides better control and responsiveness while driving.