Contract Source Code:

/**
 *Submitted for verification at Etherscan.io on 2021-02-25
*/

/*
B.PROTOCOL TERMS OF USE
=======================

THE TERMS OF USE CONTAINED HEREIN (THESE “TERMS”) GOVERN YOUR USE OF B.PROTOCOL, WHICH IS A DECENTRALIZED PROTOCOL ON THE ETHEREUM BLOCKCHAIN (the “PROTOCOL”) THAT enables a backstop liquidity mechanism FOR DECENTRALIZED LENDING PLATFORMS (“DLPs”).  
PLEASE READ THESE TERMS CAREFULLY AT https://github.com/backstop-protocol/Terms-and-Conditions, INCLUDING ALL DISCLAIMERS AND RISK FACTORS, BEFORE USING THE PROTOCOL. BY USING THE PROTOCOL, YOU ARE IRREVOCABLY CONSENTING TO BE BOUND BY THESE TERMS. 
IF YOU DO NOT AGREE TO ALL OF THESE TERMS, DO NOT USE THE PROTOCOL. YOUR RIGHT TO USE THE PROTOCOL IS SUBJECT AND DEPENDENT BY YOUR AGREEMENT TO ALL TERMS AND CONDITIONS SET FORTH HEREIN, WHICH AGREEMENT SHALL BE EVIDENCED BY YOUR USE OF THE PROTOCOL.
Minors Prohibited: The Protocol is not directed to individuals under the age of eighteen (18) or the age of majority in your jurisdiction if the age of majority is greater. If you are under the age of eighteen or the age of majority (if greater), you are not authorized to access or use the Protocol. By using the Protocol, you represent and warrant that you are above such age.

License; No Warranties; Limitation of Liability;
(a) The software underlying the Protocol is licensed for use in accordance with the 3-clause BSD License, which can be accessed here: https://opensource.org/licenses/BSD-3-Clause.
(b) THE PROTOCOL IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS", “WITH ALL FAULTS” and “AS AVAILABLE” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
(c) IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
*/

pragma solidity >=0.5.0 <0.7.0;

/// @title IProxy - Helper interface to access masterCopy of the Proxy on-chain
/// @author Richard Meissner - <[email protected]>
interface IProxy {
    function masterCopy() external view returns (address);
}

/// @title GnosisSafeProxy - Generic proxy contract allows to execute all transactions applying the code of a master contract.
/// @author Stefan George - <[email protected]>
/// @author Richard Meissner - <[email protected]>
contract Proxy {

    // masterCopy always needs to be first declared variable, to ensure that it is at the same location in the contracts to which calls are delegated.
    // To reduce deployment costs this variable is internal and needs to be retrieved via `getStorageAt`
    address internal masterCopy;

    /// @dev Constructor function sets address of master copy contract.
    /// @param _masterCopy Master copy address.
    constructor(address _masterCopy)
        public
    {
        require(_masterCopy != address(0), "Invalid master copy address provided");
        masterCopy = _masterCopy;
    }

    /// @dev Fallback function forwards all transactions and returns all received return data.
    function ()
        external
        payable
    {
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let masterCopy := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
            // 0xa619486e == keccak("masterCopy()"). The value is right padded to 32-bytes with 0s
            if eq(calldataload(0), 0xa619486e00000000000000000000000000000000000000000000000000000000) {
                mstore(0, masterCopy)
                return(0, 0x20)
            }
            calldatacopy(0, 0, calldatasize())
            let success := delegatecall(gas, masterCopy, 0, calldatasize(), 0, 0)
            returndatacopy(0, 0, returndatasize())
            if eq(success, 0) { revert(0, returndatasize()) }
            return(0, returndatasize())
        }
    }
}