>If you backup your iPhone, apps and their data don't actually get backed up. Instead, your computer just stores a list of the apps installed and where the icons were, and app data only gets backed up if the developers have used special APIs or whatever to opt-in to having the app's data be part of the backup process.

Not at all true [1].

Everything in the app's container gets backed up with the exception of the app bundle, Library/Caches/, tmp/, and other things the developer explicitly opted out.

[1] https://developer.apple.com/icloud/documentation/data-storag...