Chain ID inconsistency: some documentation references 1516, actual Arc Testnet chain ID is 5042002

[osr21]

Summary

Arc Testnet's actual chain ID is 5042002 (0x4cef52). However, some tooling references, third-party integrations, and older documentation list 1516 as the Arc Testnet chain ID. This inconsistency causes wallet configuration failures and confusing debugging sessions.

Reproduction

curl -X POST https://rpc.testnet.arc.network \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'
# Returns: {"result":"0x4cef52"} = 5042002

The actual chain ID returned by the node is unambiguously 5042002. Any documentation or tooling listing 1516 is incorrect.

Observed Instances

• Some third-party chain registry entries reference 1516 for Arc
• Some community-written guides and tutorials use 1516
• MetaMask users who follow outdated guides fail to connect because wallet rejects the wrong chain ID

Impact

• Wallet connection failures for developers following older guides
• Time wasted debugging what appears to be an RPC connectivity issue but is actually a chain ID mismatch
• Inconsistent network entries in users' MetaMask installations

Suggested Fix

1. Ensure all official documentation consistently uses 5042002 / 0x4cef52
2. Add a prominent note in the network configuration docs clarifying that 1516 is incorrect
3. Submit a PR to ethereum-lists/chains to ensure the canonical chain registry has the correct ID — this is what most wallets and tooling query automatically

Correct Configuration

Network name:    Arc Testnet
Chain ID:        5042002 (0x4cef52)
RPC URL:         https://rpc.testnet.arc.network
Currency symbol: USDC
Block explorer:  https://testnet.arcscan.app

[osr21]

Confirmed: chain ID is 5042002 — where "1516" appears

The actual chain ID is definitively 5042002 (0x4cef52):

curl -sX POST https://rpc.testnet.arc.network \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'
# {"jsonrpc":"2.0","result":"0x4cef52","id":1}  → 5042002

The chain ID 1516 may have been used in an early internal or pre-public testnet phase. It
appears in a few community-maintained lists (Chainlist, some MetaMask import guides from early 2025).

MetaMask configuration with the correct chain ID:

Chain ID: 5042002 (hex: 0x4CEF52)
RPC URL: https://rpc.testnet.arc.network
Explorer: https://testnet.arcscan.app
Symbol: ETH (cosmetic — Arc uses USDC as gas)

If you see 1516 anywhere in this repository or linked docs, it should be updated to 5042002.