The source code for the fee token contract can be found on GitHub.
The fee token contract enables builders to deposit ETH which allows them to pay for a data processing fee associated with HotShot. While the fee token contract facilitates deposits, HotShot itself manages and tracks the working balance of builder deposits. Initially, the fee token contract only supports deposits. Withdrawals are planned to be enabled in a future release.
functiondeposit(addressuser)publicpayable{//...}
The contract defines a minimum and maximum amount for deposits to avoid errors and prevent the fee table from being filled with dust.