The push notification reads:
Enjoy a good book, on us
Explore free books, read-alongs for kids, cozy mysteries, and audiobooks for the whole family.
Upon tapping on the notification, users are brought to the Free Books page in the Apple Books Store. From there users can browse through several novels from various genres, explore a wide selection of audiobooks, or select a new book from Apple’s ‘First in a Series, Free’ tab.
Apple is likely offering this promotion as people around the world remain in their homes amid the ongoing crisis. It is unclear as to how long this promotion will last, so it is definitely worth spending a few minutes to explore the many books and audiobooks while they’re available for free.