As pointed out before, Facebook's license only terminates with respect to patents (not copyright) if you sue them for patent infringement. So ... given that, th

As pointed out before, Facebook's license only terminates with respect to patents (not copyright) if you sue them for patent infringement. So ... given that, the important question is what are the actual patents that cover React? Here's why it matters. In my mind, there are basically three scenarios: (1) There are no patents. This seems the most likely scenario. Patents are public. As far as I can tell, no one's pointed to an actual React patent yet. If this is the case, then the patent grant is irrelevant. Facebook can't revoke a license for a non-existent patent. (2) There is a patent (or will be) -- but it covers some relatively new, hyper-specific feature of React. Generally speaking, patent examiners force patent prosecutors to narrow the claimed patent to avoid prior art. So in React's case, you might end up infringing the patent by using React but only if your copy of React comes with JSX, per-component state, context, and the new fibers stuff. So in order to get around the patent, you could fork React and remove per-component state or maybe you pin React to a version prior to the introduction of fibers and use that. This would super annoying for a large code base, but if Facebook actually was infringing your patent (and you thought it was a big enough deal to bring in expensive lawyers), forking React is a (relatively) small price to pay. Remember that Facebook's copyright license isn't subject to patent revocation, so forking to work around a patent is totally allowed. (3) There is a patent, and it's huge. So huge, that you can't really fork React to work around it without completely destroying what makes React work. But here's the kicker. If such a patent existed -- for the sake of argument here, let's say the patent is for components or shadow DOM -- then it probably also covers Vue.js, Angular, or whatever other framework you might want to use. That's terrible! But it suggests that the real problem isn't Facebook's PATENTS license, but the underlying patent itself (which OSS advocates should be trying to kill). At any rate, this seems unlikely -- there's lots of prior art for React out there.