This project is under the BSD license, which is equally silent about patent rights to the MIT license, making it ambiguous whether it applies to patents. The p

This project is under the BSD license, which is equally silent about patent rights to the MIT license, making it ambiguous whether it applies to patents. The patent license is on top of that; Facebook's approach is basically strictly more permissive, patents-wise, than typical use of the MIT license. (But not as permissive as the Apache 2 license, which contains explicit patent grants with a "don't sue us" condition that only applies to the specific software being licensed.) Well, there's some argument that including a patent license makes the other license less likely to be construed as implicitly extending to patents, even if it says "additional". But you really shouldn't be depending on either the MIT or BSD license counting as a patent license. See also: https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html https://writing.kemitchell.com/2016/09/21/MIT-License-Line-b... Edit: I misremembered the scope of the Apache 2 patent license, sorry.