I don't have links to any; they might be all internal. The current iteration of the patent grant was developed in collaboration with Google to meet their needs, so if there is any complaint they still have with it, that is news to me.
Only public evidence I have of this is Firebase (owned by Google) being unwilling to use React and then happy with the new license:
I would like to find out more specific information. It seems like the section of the license below says that you can never make any patent claim against Facebook or you lose rights to use the software. Doesn't that mean that Google could never initiate patent claims against Facebook, while Facebook could still initiate patent claims against Google? It seems strange that Google (or Apple) would do that. I am not a lawyer though, and the PATENTS file may not mean that.
> The license granted hereunder will terminate, automatically and without notice,
if you (or any of your subsidiaries, corporate affiliates or agents) initiate
directly or indirectly, or take a direct financial interest in, any Patent
Assertion: (i) against Facebook or any of its subsidiaries or corporate
affiliates, (ii) against any party if such Patent Assertion arises in whole or
in part from any software, technology, product or service of Facebook or any of
its subsidiaries or corporate affiliates, or (iii) against any party relating
to the Software.
Only public evidence I have of this is Firebase (owned by Google) being unwilling to use React and then happy with the new license:
https://twitter.com/KanYang/status/586636624349569024