elaborate on fee rebate cases
@@ -11,6 +11,9 @@ import "./VendingMachineAuthority.sol";
/// @dev This token is minted automatically when a TDT (TBTCDepositToken.sol)
/// is exchanged for TBTC (TBTCToken.sol) via the
/// Vending Machine (VendingMachine.sol).
+/// When the Deposit is redeemed, the TDT holder will be reimbursed
+/// the signer fee if the redeemer is not the TDT holder and Deposit is not
+/// at-term or in COURTESY_CALL.
contract FeeRebateToken is ERC721Metadata, VendingMachineAuthority {
constructor(address _vendingMachine)
