That is the onboard recording feature of the Meta Quest, it does have a way to change the video codec but the audio codec is fixed.
I'd also argue that most off the shelf stuff that records videos in any form uses AAC as a default simply because it's ubiquitous and thus has great cross compatibility.
I'd also argue that most off the shelf stuff that records videos in any form uses AAC as a default simply because it's ubiquitous and thus has great cross compatibility.