The Catalyst documentation for running iPadOS apps on a Mac is actually the worst offender. It's garbage, and unusable. Anyone who has built a Catalyst app has

The Catalyst documentation for running iPadOS apps on a Mac is actually the worst offender. It's garbage, and unusable. Anyone who has built a Catalyst app has effectively had to reverse engineer significant parts of the APIs. God only knows if some of them are supposed to be private, and if Apple will suddenly decide they are and reject apps from the store for it. I don't think there's a deliberate conspiracy here. All this stuff is launching two years before it's ready, and subject to a huge internal war at Apple - it's fairly clear a chunk of the MacOS team doesn't want to do Catalyst fearing it's the death of the Mac, even if the management do.