Last year Google started to ban donation links in FOSS apps, WireGuard was one of the first victims [0], completely removed from the store. I didn't know that Apple also started doing the same and hit WireGuard again. Extending the definition of an "in-app payment" to a link to the project homepage in the "About" window that doesn't buy any good or service related to the app is an overzealous restriction. Especially so when that button is clicked by, perhaps, only 10% of the users. This is just evil.
[0] Open-source apps removed from Google Play Store due to donation links