Maybe the word “audit” is incorrect? If they didn’t provide you any guidelines, I’d definitely recommend asking. But it’s possible they’re just looking for your perspective on best practices and possible improvement ideas, more like a general code review.
Software devs in general seem to have a hard time with balance. No comments or too many comments. Not enough abstraction or too much, overly rigid or loose coding standards, overoptimizing or underoptimizing. To be fair it is difficult to get there.