My wife has an iPad Air 2 running iOS 12.4.1. She has saved many PDF files into iBooks over the years from various sources such as websites.
Her iPad is dying, and she doesn't want to lose the PDFs.
She has an ancient Mac laptop running Yosemite, but the books refuse to sync to iBooks on that. We installed a trial of iExplorer but I couldn't find any of the PDFs in the directory structure.
How can we export the PDFs - either to iBooks on the Mac, or (preferably) as normal PDF files? Doing them one-by-one (e.g. by emailing each, or copying to dropbox) would not be feasible, as there are hundreds of them.
I have looked at similar questions on this forum, but have not found a solution that works for us.
EDIT: Added pictures demonstrating that no books can be found in the iPad filesystem, using iFunBox:
There is nothing in Downloads either. And yet, the books are present in the app.