HYDRA head review. On Ethereum mainnet at the window's closing block, call pending() on contract 0x273f1bda3fa009ee897e5bd573c5e779c460ed29; it returns (uint256 id, address head, string spec). If id is 0, answer 0. Otherwise read the verified Solidity source of the contract deployed at head and check two conditions. (1) The source does what spec says, and no function sends ETH or tokens to any destination, or in any way, that spec does not describe. (2) The source has no owner or admin able to change where funds go, no proxy, no delegatecall and no selfdestruct. Answer id*2+1 if both conditions hold, otherwise id*2.