Can anyone tell me how this clause is interpreted when I use React in Germany?
German law (simplified) claims that no software patent is valid unless it solves a technical problem (in the physical problems sense).
Does this mean since I accept German law as valid by being a citizen of the country I implicitly claim some (ergo any) Facebook patents are invalid and the clause triggers automatically?
Is living in such a country enough or do I have to actively state "Facebook patents..invalid IMO"? What about the German government itself using React?
I'm mostly interested in the interpretation since it's a curious use case.
The actual grant you'd lose is pretty much useless in that scenario either way (as it can't really be granted due to the software not patentable issue).
Are there ever! For example, right against self-incrimination must now be invoked explicitly. Refusing to answer a question (they will say "being evasive") can be used against you unless you affirmatively state you are exercising your right to remain silent. [1]
Facebook holds patents granted in the US. Those patents to do not apply to all other jurisdictions. German law doesn't consider US software patents invalid, they just don't apply under German jurisdiction.
Basically, if Facebook can't sue you for patent infringement in the first place, the clause doesn't apply. If you use React in a product that enters the US market (or any market that is subject to US patent law), that's a different story.
That said, I'm suspicious that the entire thing is not enforceable in Germany in the first place (to clarify: I'm not claiming it's invalid, just speculating that it may not be enforceable in German courts). German contract law is actually pretty restrictive when it comes to what may or may not be in implicit agreements like software licenses.
Case in point: WhatsApp was told off in Germany because it blocked the accounts of users who used third-party clients. Using third-party clients was explicitly forbidden in the WhatsApp ToS, but the clause was considered "surprising" and therefore invalid. The ruling argued that using third-party clients was accepted by most popular similar apps and losing access (not just in the third-party client, but in WhatsApp proper) because of doing that could not reasonably be expected by users.
There are also serious restrictions to what rights you can waive. Not only doesn't the public domain exist in German law (you can grant a universal unrestricted non-exclusive license, but you can't waive your ownership completely), nor can you completely disclaim responsibility (e.g. you can still be sued for intentional harm even if you give something away for free). Another example was Walmart in Germany trying to prohibit employees from entering romantic relationships with each other (and failing, resulting in lots of bad PR).
There's a reason contracts in Germany typically include a clause stating that even if any single clause is legally invalid the other clauses (or even "the spirit of those clauses" in so far as it can be enforced otherwise) still remain in effect. I'm not sure whether this is actually required, but the idea is that it prevents contracts from becoming invalid because of any single clause being ruled invalid.
I'm mostly interested in the interpretation since it's a curious use case. The actual grant you'd lose is pretty much useless in that scenario either way (as it can't really be granted due to the software not patentable issue).