Earlier quoted context omitted.
Me either. I had no idea that accessing a link to NFT-described content went through OpenSea for content that isn't even hosted by OpenSea. That's apparently a MetaMask thing. Supposedly a MetaMask wallet can connect to any willing node, but in practice they use the Infuria->OpenSea server. Yes, you can run your own Etherium node and server, and connect a MetaMask wallet to it.[1] As Moxie points out, nobody wants to…
> Worse, the blockchain does not, apparently, contain the hash of the data. It very often does, and it is certainly the case for most high-value NFTs. It is indeed not the case if you create your NFT on OpenSea and do not take the additional step of freezing the metadata. Also, there are many artworks that change, so a hash to a single file is not necessarily the right solution.
In those cases does the blockchain still have the URL as well? And you might end up with a collection of bits that matched the hash in the blockchain but was no longer at the original URL? What's the next step then?
(The "artwork may change" bit seems like it becomes even more weird and potentially nightmarish edge-case/potentially-losing-your-purchase-wise.)