Take a look at https://github.com/code-423n4/2024-03-zksync/blob/4f0ba34f34a864c354c7e8c47643ed8f4a250e13/code/contracts/ethereum/contracts/state-transition/chain-deps/facets/Mailbox.sol#L197-L227
This mechanism allows users to deposit ETH from L1 to L2 into two separate addresses within zkSync Era, which introduces a unique feature not found in the traditional Ethereum Virtual Machine (EVM) environment.
Users can deposit ETH to a contract address (_contractL2) and simultaneously direct a refund to a different recipient address, by specifying a different address from _contractL2 . This dual-address deposit capability deviates from standard EVM practices, where transfers from an externally owned account (EOA) to two addresses simultaneously are not possible. This feature, specific to the zkSync Era, enables such transactions.
Undocumented deviation from the Ethereums VM
To mitigate any potential confusion and enhance security awareness, its crucial to thoroughly document this dual-address deposit process.
