Comment by cosmic_cheese
7 days ago
The behavior of the (now option-clicked) zoom button is actually determined by each individual program. Most stock apps will either fit to content or toggle between the last two recent sizes, but a lot of third party apps (especially those built with foreign UI frameworks) tend to turn it into a maximize button.
It looks like "apps built with foreign UI frameworks" includes all the stuff Apple's written in SwiftUI, as all those apps (Mail, Calendar, Messages, Music, Podcasts, Notes, etc) treat zoom as maximize.