0confirmation utilizes a Gas as a Service protocol to enable users to swap their bitcoin using uniswap without ever having to have ETH. Whenever a transaction is published to the network and a keeper picks it up the keeper uses their own ETH to pay the gas for it. The protocol estimates the amount that should be paid and calculates the value in BTC terms. The Keeper is paid this amount out of the shifted renBTC. The estimated amount of BTC that will be used for gas is displayed in the fee portion of the app.