Mostly a bunch of pretty-reasonable clarifications, but there's also a few that seemed aimed at Epic Games and co. Changes from previous guidelines in italics:
> 2.3.1: Don’t include any hidden, dormant, or undocumented features in your app; your app’s functionality should be clear to end users and App Review. All new features, functionality, and product changes must be described with specificity in the Notes for Review section of App Store Connect (generic descriptions will be rejected) and accessible for review.
> 3.1.3 [...] Apps [allowed to use payment methods other than IAP] cannot, either within the app or through communications sent to points of contact obtained from account registration within the app (like email or text), encourage users to use a purchasing method other than in-app purchase. [previous: You must not directly or indirectly target iOS users to use a purchasing method other than in-app purchase, and your general communications about other purchasing methods must not discourage use of in-app purchase.]
> 2.3.1: Don’t include any hidden, dormant, or undocumented features in your app; your app’s functionality should be clear to end users and App Review. All new features, functionality, and product changes must be described with specificity in the Notes for Review section of App Store Connect (generic descriptions will be rejected) and accessible for review.
> 3.1.3 [...] Apps [allowed to use payment methods other than IAP] cannot, either within the app or through communications sent to points of contact obtained from account registration within the app (like email or text), encourage users to use a purchasing method other than in-app purchase. [previous: You must not directly or indirectly target iOS users to use a purchasing method other than in-app purchase, and your general communications about other purchasing methods must not discourage use of in-app purchase.]