I found this: https://developer.apple.com/forums/thread/762784 Looks like share ...

		colinnordin 6 months ago \| parent \| context \| favorite \| on: Spaced repetition systems have gotten better I found this: https://developer.apple.com/forums/thread/762784 Looks like share extensions are not generally available inside the Books app, which is why my app is not showing up. Thank you for making me aware of the issue!