Deposit Custody

All deposits in Mezo are held in a locking contract that holds funds until they can be bridged at Mezo mainnet launch. The locking contract is upgradeable by the 5-of-9 multisig run by Mezo's development team. These upgrades will allow additional collateral to be included in the future, as well as enabling bridging at launch. The funds are not retained by the multisig.

BTC deposits are bridged to tBTC before being deposited in the locking contract.

The locking contract holds wBTC or tBTC (whichever was deposited) and will enable withdrawal of the original deposited currency (including BTC for BTC deposits) when deposits unlock.

You can find info on tBTC bridging and its custody model here.