According to Foresight News, the cross-chain bridge between Polkadot and Kusama is now operational. Concurrently, the GRANDPA light clients running on the separate BridgeHubs of Polkadot and Kusama have been initialized. These are currently being synchronized in real-time by a permissionless relay run by Parity. The consensus proof logic (light client), parallel chain header proof logic, and message proof logic all operate on-chain during the BridgeHub runtime, completely controlled by Polkadot/Kusama governance.