Are there any of these around? Not bitcoin addresses, but bitcoin xpubs - public keys, from which you could create a watch-only wallet.
I'm thinking maybe from entities that want to prove that they truly own the bitcoin that they say they own?
Or from anywhere, really. I just want to experiment.
m/84'/0'/0'/0:xpub, I am assuming you mean "eXtended public key`, per BIP-0032.Private key == Secret key- it's the same thing. I'll stick toprivateto reduce confusion now.xpub, and thexpubitself, then they can calculate all the private keys underneath thatxpub- i.e. essentially thexprv. And yes, "your key, your coin" is also valid, so if you know the private key for any funds on chain, they are "yours".