That's pretty interesting. So, the three non-backed locations are tmp, Caches and the Application Bundle. tmp and Caches are now swept. So, if you store your real cache stuff in the Application Bundle, it won't be backed up or auto-deleted. But maybe it gets trashed when you update the app.

I wonder if OS X, in line with its trend to be more like iOS, is going to start automatically clearing the ~/Library/Caches directory as well.