I was wondering about a similar issue for zstd compression library. It has a similar BSD+Patentsfile thing. There is an issue with a related discussion about it going for more than a year: https://github.com/facebook/zstd/issues/335 Last update is interesting. Someone did a search and looked for any patents FB filed for and couldn't find any in last year. So somehow based on that they decided things are "OK". To quot…
And I'd find it highly unlikely it contains any patents too. Occulus was bought in March 2014 by Facebook and RakNet was bought in April 2014 by Occulus and there is only a handful of commits on GitHub that don't seem substantial at all and are just maintenance and cleaning up the repo. RakNet operated for years before that so it's unlikely they happen to have had a patent in it at the time of its purchase or they'd be nuked by Facebook before.
Then again, there are/were patents for some bit tricks and Carmack's Reverse so anything is possible.