I have read in various places that NFTs can be created which pay a transaction fee payable to minter of the NFT when it is transferred between owners.
But I don't see in the ERC 721 spec where that property (the amount paid to the creator on transfer of the token) is defined and "written" into the token. I wonder whether fees payable to creators on each sale of a NFT an off chain transaction by the platform on which the NFTs are bought and sold, rather than embodied feature of the NFT enforced by the blockchain transfer mechanism? If it is embodied, where is it specified?