You should only cast a vote on this proposal if you want to veto this protocol upgrade.

Upgrade 21 - Interop Readiness introduces the following capabilities to the OP Stack:

• ETHLockbox on every chain: Gives every chain a single way to hold bridged ETH and a single place to apply a chain-specific pause, laying the groundwork for interop.
• Withdrawal path hardening: A withdrawal that can't be relayed on L1 now stays retryable instead of being finalized as failed, and anyone can delete withdrawal proofs on dispute games resolved against them.
• OPCM v9.0.0: Updates the contract upgrade manager to lower gas for upgrading multiple chains at once and to check that chains have the new lockbox and pause setup.

This is an optimistic approval. You should only cast a vote if you want to veto this protocol upgrade. You can read more about this proposal type in our operating manual. You can read the proposal in its entirety here.