They removed the prime logo from eligible books, but it looks like the Kindle Unlimited logo is still out there. Any KU book will be eligible to be read as a KOLL.That might be of some help. But you still have to do the actual borrow from your kindle device. From the device, you go to the KOLL selection list. But from a computer, I'm guessing you'll have to search via Kindle Unlimited books, it might miss a few, but I can't find another option since they removed the Prime button from the books.
UPDATE
I did some looking around and found this link which was posted on an ebook blog which seems to show the KOLL eligible books. I'm not sure how Amazon;s latest changes will affect it, but it worked when I wrote this. Hope it helps:
Prime Eligible Books
