[frabcus]

How can they claim this text file applies?

There is also a file with the industry-standard name LICENSE (https://github.com/facebook/fbcunn/blob/master/LICENSE), with a standard looking BSD license in it.

Surely somebody using it could claim that was the file that applied, and this other non-standard whimsical "PATENTS" file was irrelevant?

Or can people just bury random licenses deep inside copyrighted works, and expect them to apply?

[mcintyre1994]

Does that BSD license grant a patent license though? It doesn't seem to. Otherwise arguing their "PATENTS" file doesn't apply means you have no right to any patents exercised by the software anyway.

All it does is grant rights, albeit flimsy ones that can be taken away in stupid circumstances. There's no real use arguing it doesn't count because then you're just saying you never had those right and are infringing in exactly the same way.