It also allows a user to modify the fee for the top level domain ID of the given NFT. What does this mean? Let's say a given subdomain zero.cats.fluffy, this means that the top if the top level domain zero has an associated fee, that amount will be subtracted from that bid and sent to the owner of the top level domain. The fee that this domain has can be altered by the domain owner to values between 0$ and 10%, given 5 decimal places of precision. This means 1% is 100000, 5% is 500000, 7.89% is 789000, etc.