For any Arthur-heads excited that the new lore just dropped, this is a copy of a previously documented rare manuscript rather than new material:

There are less than 40 surviving copies of the Suite Vulgate du Merlin text known to scholars, and since medieval scribes copied them by hand, each is a unique version. The one found at Cambridge University Library, for example, has decorative red and blue initials. Based on this as well as other features, the researchers suggest the text was written between 1275 and 1315.

That does not detract from the incredible work done here in any way, just wanted to make sure it's clear these are not previously unknown writings.