Add a Chain: BattleChain Mainnet (eip155:626)

[Equious]

Adding a new chain to the Explorer

1. JSON-RPC spec for Wallets — not needed; BattleChain is EVM-based and uses the existing Ethereum eip155 JSON-RPC spec.
   GitHub Link: https://docs.walletconnect.com/2.0/advanced/rpc-reference/ethereum-rpc
2. CASA namespace spec — not needed; the eip155 namespace already exists.
   GitHub Link: https://github.com/ChainAgnostic/namespaces/blob/main/eip155/caip2.md
3. namespaces: eip155
4. chains:
   • eip155:626 — BattleChain Mainnet (mainnet)
   • eip155:627 — BattleChain Testnet (testnet)
5. RPC endpoints:
   • Mainnet: https://mainnet.battlechain.com
   • Testnet: https://testnet.battlechain.com
6. SLIP-0044 coin type: 60 (ETH — BattleChain is a ZKsync-based Ethereum L2 with native ETH)

References

• Source of RPC endpoints: https://battlechain.com — merged into ethereum-lists/chains (Add BattleChain Mainnet (chainId 626) ethereum-lists/chains#8426), file _data/chains/eip155-626.json
• Source of namespace / chainId info: https://chainid.network (chainId 626), ethereum-lists/chains eip155-626.json

Additional context
BattleChain is Cyfrin's ZKsync-based Ethereum L2 (mainnet live, chainId 626). Explorer: https://explorer.battlechain.com. Already integrated in viem (wevm/viem#4739), per the EVM recommendation in your chain-onboarding docs.

• I have read and understood the above clarification

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CR-825