Contract Source Code:

// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity ^0.8.12;

/**
 * A wrapper factory contract to deploy SmartAccount as an Account-Abstraction wallet contract.
 */
interface ISmartAccountProxy {
    function masterCopy() external view returns (address);
}

/// @title SmartAccountProxy - Generic proxy contract allows to execute all transactions applying the code of a master contract.
contract SmartAccountProxy is ISmartAccountProxy {
    // singleton 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 singleton;

    /// @dev Constructor function sets address of singleton contract.
    /// @param _singleton Singleton address.
    function initialize(address _singleton, bytes memory _initdata) external {
        require(singleton == address(0), "Initialized already");
        require(_singleton != address(0), "Invalid singleton address provided");
        singleton = _singleton;

        (bool success,) = _singleton.delegatecall(_initdata);
        require(success, "init failed");
    }

    function masterCopy() external view returns (address) {
        return singleton;
    }

    /// @dev Fallback function forwards all transactions and returns all received return data.
    fallback() external payable {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let _singleton := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
            calldatacopy(0, 0, calldatasize())
            let success := delegatecall(gas(), _singleton, 0, calldatasize(), 0, 0)
            returndatacopy(0, 0, returndatasize())
            if eq(success, 0) { revert(0, returndatasize()) }
            return(0, returndatasize())
        }
    }
}