We've seen b before. React was controversially released with a similar clause and ultimately Facebook dropped it and used a standard open source license. Their lawyers really love this idea for some reason.
We used to call b the Disney/LEGO clause. Disney was famous for litigating any GenAI product for copyright infringement if it was able to recognize or god-forbid generate any of their IPs.
So the lawyer cats would slip that clause into all licenses.
Personally i think it's fair. You get to use this model as long as you don't sue Meta because of the model's weights or outputs.
Was it released with it? Iirc they tried moving to such a license from bsd, which contains no patent grants whatsoever, and hence they thought it was a strict upgrade. The community did not agree so they moved back.
Do their lawyers love the idea? Hard to say. My guess is, Zuck really likes the idea, so he keeps directing them and their chief counsel to try stuff like this.
It's almost as if having a CEO of a company placed beyond the control of the corporate board is a bad thing.
This is a pretty common clause when a company open sources something that was previously locked away. The AOM AV1 codec has a similar rule for its patent pool to discourage trolling.
Personally i think it's fair. You get to use this model as long as you don't sue Meta because of the model's weights or outputs.