From GitHub:

This will need to be executed by the Threshold Council because they have ownership of the contracts. We should give them JSONs to load into Safe. Navigate to tx builder and prepare JSON for each chain: • [ ]  ArbitrumSafeContract ABI scroll to the bottomProxy address gateway: https://arbiscan.io/address/0x1293a54e160D1cd7075487898d65266081A15458Arbitrum transaction JSON executing 'updateGatewayAddress()' with Base chain ID: 30 • [ ]  OptimismSafeContract ABI scroll to the bottomProxy gateway address: https://optimistic.etherscan.io/address/0x1293a54e160D1cd7075487898d65266081A15458Optimism transaction JSON executing 'updateGatewayAddress()' with Base chain ID: 30 • [ ]  PolygonSafeContract ABI scroll to the bottomProxy gateway address: https://polygonscan.com/address/0x09959798B95d00a3183d20FaC298E4594E599eabPolygon transaction JSON executing 'updateGatewayAddress()' with Base chain ID: 30

Links to transactions:

  1. Arbitrum: https://app.safe.global/arb1:0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f/transactions/multisig_0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f_0x796458d0aed5984c5355c0ea7f479c28c809c024d7a05f8a3e158ca107b97725
  2. Optimism: https://app.safe.global/oeth:0x7fB50BBabeDEE52b8760Ba15c0c199aF33Fc2EfA/transactions/multisig_0x7fB50BBabeDEE52b8760Ba15c0c199aF33Fc2EfA_0x0391195d68969e778486acd8103f65fe5c27f7d6a4deed4bdcaa256b41c6f8b7
  3. Polygon: https://app.safe.global/matic:0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f/transactions/multisig_0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f_0x28a46a7187be2b9a68ba31b9d2751dbb05b6f450d070a2483171467a5015e714

Council MS addresses:

  1. Arbitrum: arb1:0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f
  2. Optimism: oeth:0x7fB50BBabeDEE52b8760Ba15c0c199aF33Fc2EfA
  3. Polygon: matic:0x9F6e831c8F8939DC0C830C6e492e7cEf4f9C2F5f

From Dymitr:

Council, before we can announce x-chain Base support we need to map Base gateway address in the existing supported chains: Arbitrum, Optimism and Polygon. Here are the JSONs that should be dropped in the transaction builder in all 3 chains, signed and executed.

Base gateway address: 0x09959798B95d00a3183d20FaC298E4594E599eab https://github.com/keep-network/tbtc-v2/blob/main/cross-chain/base/deployments/base/BaseWormholeGateway.json