Hey,
As gnome-books was split off from gnome-documents upstream, packaging
gnome-books would have required a new package to be introduced. As
gnome-books is already available as a Flatpak from the upstream maintainer
on Flathub, and no one else volunteered a new package, I've made gnome-books
obsolete in Fedora.
The change has been made in fedora-obsolete-packages:
https://src.fedoraproject.org/rpms/fedora-obsolete-packages/pull-request/14
And gnome-documents has been updated to the latest 3.31 release in rawhide/F30.
Regards