A new plugin is added to the existing Remix plugins. The plugin is an adapted version of the verification plugin (clean-up of unused functionality still needed): https://github.com/ethereum/remix-project/tree/master/apps/contract-verification.

The plan is to add 3 features:

• Feature 1: Fetching ABI from blockexplorers/sourcify (for a verified contract address) to get a UI to interact with a contract (similar to the UI in the Deploy & Run transactions tab).
  It could have four sections for proxyread/proxywrite/implementationread/implementationwrite category.
  https://github.com/DOBEN/ETHGlobal2024
  This feature does not add much value on its own (similar to fetching the source files from the block explorer https://github.com/ethereum/remix-project/blob/master/apps/contract-verification/src/app/Verifiers/EtherscanVerifier.ts#L217), but this step can be seen as a preparation for easily achieving Feature 2 once block explorers provide an API endpoint for fetching decode ABI.

• Feature 2: Fetching/Decoding ABI (for unverified contract addresses) to get a UI to interact with a contract (similar to the UI in the Deploy & Run transactions tab) and lookup the decoded function selectors in a function selector database.

We hope for a public API to query decoded ABI from blockscout database (up to blockscout’s discretion so when and if this will be available).
blockscout/blockscout#11099

• Feature 3: Decoding the return parameter (for unverified contract addresses)