Contracts

The call

if (provider.capabilities.contractInfo && provider.getContractInfo) {
  const contract = await provider.getContractInfo(address, "ethereum");
}

Etherscan and Blockscout serve it, on every EVM chain they cover. No other provider does, and getContractInfo is absent on them rather than present and useless.

The shape

interface ContractInfo {
  address: string;
  isVerified: boolean; // source available on the explorer
  isProxy?: boolean;
  implementationAddress?: string; // when isProxy
  name?: string;
  compilerVersion?: string;
  abi?: string; // JSON string, as the explorer sends it
  sourceCode?: string;
  isToken?: boolean;
  tokenStandard?: "ERC-20" | "ERC-721" | "ERC-1155";
  creator?: string;
  creationTxHash?: string;
}

isVerified means the explorer holds source that compiles to the deployed bytecode. It says nothing about whether the code is sound, and nothing about the implementation behind a proxy, which is its own address with its own verification. When isProxy is true, read implementationAddress next; the ABI you want is usually there.

abi stays a string so nothing here parses somebody else's JSON on your behalf. JSON.parse it when you need the entries.

CLI

explorers contract 0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984
explorers contract 0x… -c base -p blockscout

In the explorer

The Explorer shows the metadata, the number of ABI entries and the length of the source, not the source itself. A verified contract's source can run to hundreds of kilobytes and a demo page is not where to read it.