How is Robinhood Chain different from Arbitrum?
Robinhood Chain is built with Arbitrum's Nitro stack as an Orbit chain, so it shares Arbitrum's execution semantics, transaction types and tracing model. The difference is purpose: it hosts native tokenized US equities, which Arbitrum One does not.
Practically, that means everything you know about Arbitrum applies — transaction type codes 100 through 106, address aliasing for cross-chain senders, l1BlockNumber and sendRoot on blocks, and the Stylus tracer for WASM contracts.
What does not carry over is the data model above the EVM. Stock tokens implement ERC-8056 and express dividends and splits through a multiplier, which no Arbitrum One tooling accounts for. Generic Arbitrum indexers will index the transfers correctly and value the positions incorrectly.