> React is Bsd, this one is also bsd-ish?

But this one comes without Facebooks patent clauses.

Edit: Apparently that was too terse: While Facebooks React comes as BSD, the patents clauses are so broad that questioning software patents in a blog post would result in licence revocation. They are not just litigation defense like the ones from the Apache Foundation:

"The license granted hereunder will terminate, automatically and without notice, for anyone that makes any claim [...] alleging [...] that any right in any patent claim of Facebook is invalid or unenforceable."

It is probably the case (but not guaranteed) that a court would read "makes any claim" a bit more narrowly to mean only legal claims, not blog posts. It's a common phrase used in e.g. statutes as a term of art, and usually taken as narrower than a phrase like "expresses a view". However it would almost certainly still include USPTO administrative challenges (e.g. challenging a patent by demonstrating prior art), which is still a big problem.

This comes without any patent grants whatsoever. If you're worried that Facebook has patents covering react, you should probably be worried that they have patents covering this code as well. If you're worried about the patents, you should use react or use neither.

Facebook has some nasty patent terms in their open source projects.

Wow, yeah. Read the PATENT file in a bit more detail now. Could be a problem.