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.
>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.
"hereunder" does not refer to a direction within the text :)
>further on in a document.
Even your primary definition contains the location clause, 'under the terms'.
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