Eth call, Optimism contract call. Read-only contract call on Optimism (eth_call): send ABI-encoded calldata to a contract at the latest block and get the raw return data, without a transaction or gas. Use to read any view function that has no dedicated tool (the example reads USDC totalSupply, selector 0x18160ddd); decode the result with the function's ABI. Calldata up to 8 KB; a call that reverts is 422 with the reason, uncharged.