Wormhole contracts are managed via governance by the guardian set. There are currently several pre-defined governance actions that the wormhole contracts can perform ranging from contract upgrades to guardian set updates. These actions are emitted as normal wormhole messages by a governance contract, which exists at the following pseudo-location:
Governance messages can target any of the various wormhole modules, including the core contracts as well as all currently deployed token bridge contracts. When a guardian signs such a message, its signature implies a vote on the action in question. Once more than 2/3 of the guardians have signed, the message and governance action are considered valid.
Governance messages contain pre-defined actions, which can target the various wormhole modules currently deployed on chain. The structure contains the following fields:
u8 module Contains a right-aligned module identifier
u8 action Predefined governance action to execute
u16 chain Chain the action is targetting, 0 = all chains
... args Arguments to the action
Here is an example message containing a governance action triggering a code upgrade to the solana core contract. The module field here is a right-aligned encoding of the ASCII "Core", represented as a 32 byte hex string.
The meaning of each numeric action is pre-defined and documented in the wormhole design documents. For each application, the relevant definitions can be found via these links: