IANAL, but the argument seems to be that there is an implicit patent grant in the MIT license. MIT gives you a license to use the software, and you can't use the software without a patent grant, therefore you have an implicit patent grant. The existence of an explicit patent grant means that you can use React without an implicit patent grant, so you don't just automatically get one if you lose the explicit patent grant.

Wouldn't that implicit patent grant be in every other BSD-style license as well?

As far as I understand it, the patent grand terminates when you end up in court with Facebook and then you're effectively distributing software that may or may not be covered by patents you don't own/have a license for.

No, being in court with Facebook is only one place where the termination can happen:

>anyone that makes any claim (including by filing any lawsuit, assertion or other action)

Even just stating that a Facebook patent is invalid terminates your license.

>any right in any patent claim of Facebook is invalid or unenforceable

Even just stating your belief that software patents are invalid or unenforceable terminates your license.

However, if you read closely, the last paragraph starts out with:

>The license granted hereunder

There isn't actually any license granted after that clause (it occurs before this clause), so I'd argue the entire last paragraph is meaningless puffery.

> There isn't actually any license granted after that clause (it occurs before this clause)

"hereunder" does not refer to a direction within the text :)

Yes, it does.

google "define:hereunder" -> "as provided for under the terms of this document."

With sub-qualification:

>further on in a document.

Even your primary definition contains the location clause, 'under the terms'.

> with a sub-qualification

Odd, that didn't show up in my view o_O Maybe google is geo-targetting dictionary definitions...

Also, 'under the terms of this document' does not literally mean 'physically located beneath this sheet of paper' :P

It can. But it doesn't necessarily.

Nothing better than ambiguous language in psuedo-legal documents.

> Even just stating your belief that software patents are invalid or unenforceable terminates your license.

I guess that's the interesting part. Sources would be really helpful.

The second link I included in the comment above was to DannyBee's discussion of implicit vs explicit patent grants.

Thanks for the pointer.