What is Audi A6's Quattro All-Wheel Drive System and how does it work?

I've been hearing a lot about the Quattro All-Wheel Drive system in the Audi A6 but I'm not sure how it differs from other AWD systems. Can anyone provide an overview of how it works and what makes it unique?

The Quattro AWD system in the Audi A6 is one of the most advanced systems on the market. It uses a center differential to distribute power to all four wheels, ensuring maximum traction and control in all driving conditions. Unlike other AWD systems, Quattro can send up to 85% of power to the rear wheels, giving the A6 a sportier and more balanced feel.