This post has more information on what the patent grant is: https://code.facebook.com/posts/1639473982937255/updating-ou...

Where would I have to ask to get legally binding information on the specific patents for this bot?

I am definitely not going to use its source (due to licensing issues with Facebook already), but if there is even a tiny chance that the idea is patented, I won’t touch it either.

I could be wrong and IANAL, but I doubt you'll be able to get lawyers for Facebook to spend time on request to figure out which patents might cover a particular piece of code - especially since I think telling you there aren't any might let you claim estoppel in the (extremely unlikely) case they actually wanted to sue you.

But you can get a list of Facebook's patents here:

http://stks.freshpatents.com/Facebook-Inc-nm1.php

edit: Of course, just because they're including patent boilerplate doesn't mean anyone actually did this research in the first place or believes that a particular patent covers it; I would be surprised if someone had, as opposed it just being standard boilerplate (although it doesn't seem to be on all their projects). There's little reason to worry more about patents on this project than on any other open source project distributed under a BSD license, without an "additional" grant of patent rights. Not none, but little.

Well, I distrust this kind of software patents in general, and (this violates Facebook’s patent grant) think most of them are invalid, including many which Facebook owns.

So, as I directly and openly violate their grant, I’d prefer to make sure that their patents either (a) don’t apply in Germany, or (b) are invalid, or (c) they don’t actually have patented a specific kind of idea.

Sadly it is next to impossible to get a patent for software in germany. It has to interface with some kind of hardware (like an engine control software in a car or plane). A bot or something similar that only runs on a computer can't be patented in germany.

I am german myself and work on a research project and we tested some software on our participants and they loved it. So we thought about protecting our idea / software.

For that reason we attended a talk held by multiple patent lawyers specialised in germany law and all of them said the same: "It can't be done without a hardware interface".

Thanks, that's helpful. It still strikes me as presumptuous to "grant" a patent license to non-patentable and un-patented material, but I suppose it makes sense from a cover-your-ass point of view.

They are not claiming this specifically is patented, this is standard boilerplate on all their projects.