Why does my Audi A6 engine keep revving while idling?

I've noticed that while my 2018 Audi A6 is in park and idling, the engine revs up and down. It doesn't seem to affect performance, but I'm curious as to why this happens.

It's likely due to a faulty idle air control valve. This valve regulates the airflow into the engine when the throttle is closed. When it malfunctions, it can cause the engine to rev up and down instead of maintaining a consistent idle speed.