hyperlane-monorepo/solidity/contracts/interfaces/IGasOracle.sol

// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity >=0.8.0;

interface IGasOracle {
    struct RemoteGasData {
        // The exchange rate of the remote native token quoted in the local native token.
        // Scaled with 10 decimals, i.e. 1e10 is "one".
        uint128 tokenExchangeRate;
        uint128 gasPrice;
    }

    function getExchangeRateAndGasPrice(
        uint32 _destinationDomain
    ) external view returns (uint128 tokenExchangeRate, uint128 gasPrice);
}