The address page carries a contract detection block. For each chain it answers whether contract code sits at this address: a contract is a program on the blockchain, an ordinary account is not.

The third state, not checked, matters. It does not mean "no contract sits there", it means "we could not look": either no endpoint is configured for that chain, or the endpoint did not answer, or the page's query budget was used up. An unchecked chain may still carry a contract.

If two chains are marked as a byte-identical group, the same program is deployed on both. Their state can still differ: balances, owners and settings are independent per chain.

For Bitcoin, Solana, TRON and XRP addresses the block does not appear, because the chain is already evident from the address format.