According to this Chevy explanation video,

the 2023 Chevrolet Corvette Z06 boasts a smart intake system to improve airflow, but engineers didn't overlook the exhaust.

The Z06's LT6 5.5-liter V-8 generates a sound unlike any other Chevy V-8 thanks to its flat-plane crank and fast revving nature—

a unique howl in place of the conventional American V-8 rumble. Engineers wished to highlight that distinctive sound.

In order to do this, the bezel housing the quad exhaust tips of the Z06 was created to reflect part of the sound back into the cockpit. 

Two sets of valves—one on the intake manifold and the other on the exhaust—can also be used to modify the sound.

Active exhaust systems are nothing new, 

however the Z06 system allows the valves to be adjusted in 2-degree increments as opposed to the prior systems' ability to just flip from fully open to fully closed. 

This enables specialised tuning for the four driving modes—Weather, Tour, Sport, and Track—of the Z06.

The weather is the most silent mode and keeps the valves mostly closed. The mode is "don't irritate your neighbours." 

Tour maintains common decency while slightly opening the valves. Sport goes a little further, whereas Track is intended to be quite loud. 

Additionally, Chevy included a My Mode for unique settings.

The LT6 V-8's exhaust system not only produces a beautiful symphony but also 670 horsepower and 470 lb-ft of torque without the need of forced induction.