There's been some confusion from Ubisoft today around which of their PS4 games are not going to be compatible through backwards compatibility on PS5, and I just wanted to share this information for some added clarity on things while we wait for the review embargos to end or Sony to comment further.
The new
https://library.playstation.com web site references an API which it will try to access to determine the BC status of your games. You can see this via the web developers console on your browser, but for the benefit of everyone I've scraped the information from this API for every known PS4 title ID (or at least I believe) and published it here:
https://andshrew.github.io/supreme-enigma/
At the moment there are three BC states; COMPATIBLE, BOOTABLE, NOT_COMPATIBLE. Some title ids are not in this BC database and so I have listed these as N/A (these appear to be mostly beta versions of titles and demos, and so presumably are not in consideration for compatibility). I can't offer any further insight into what BOOTABLE actually means, but if you take it at face value (and the fact that Sony did not list these are incompatible) then it means they are playable in some form on the PS5.
Also note that I've listed every individual title ID here and a single game may have several IDs for the various regional releases, which is why the total number is so high.
The only other thing to consider with this data is that it is clearly still a work in progress; last week this same API reported that P.T was compatible but now lists the game as incompatible (so it's possible some of the Ubisoft games are later amended in the same way).