I have no idea but that would be ridiculous. I don't even believe in "intelectual property".
Does nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6 have proprietary ownership of #Nostr? In the sense that he has a legal claim to it in any way? #asknostr
Discussion
My concern is mainly directed at government considering aspects of it your legal property and using it as an attack vector against you and the network.
Imagine most com platforms are fully KYC a few years from now, there’s another round of lockdowns or a similar crisis, and people are flocking to Nostr to organize themselves. There is a possibility that your local government, even foreign governments, would attempt to prosecute you or prominent developers in this scenario. If you have legal claims, they could attempt a takeover of those. Would it affect the network in any way? I don’t know… just thinking out loud here. 
At least in America software licenses and according property rights are well established. If it’s open source(which nostr is) this concern is mitigated. Nostr is also a protocol, not proprietary SaaS product run by a company, so it’s very different there too. This would be like saying Linux is the personal private property of Linus Torvalds.