NFT owner, Ethereum. Owner of an NFT on Ethereum: the wallet that holds one ERC-721 token id right now (ownerOf), plus the collection's name and symbol. Use to verify who holds an NFT before a trade, a mint gate or an airdrop; for how many a wallet holds use eth_nft_balance, for the token's metadata eth_nft_metadata. A missing contract is 404, a token that does not exist 422, both uncharged.