On which chain is dYdX?

Could you elaborate on the underlying blockchain technology that powers dYdX? I'm curious to know which specific chain it's built on, as it's crucial to understand the infrastructure and capabilities it offers. Could you provide a brief overview of the chain's key features and how they contribute to dYdX's functionality? Additionally, is there any interoperability with other blockchains, or are there plans for future integrations? This information would be valuable in assessing dYdX's position in the decentralized finance landscape.