ChainSafe has released a prototype of Zipline Casper, a trust-minimized, cross-chain block header oracle. It verifies the origin chain's finality protocol, providing economic security. Zipline can be used for cross-chain applications or to enhance existing ones. The project originated from a hackathon and was awarded a grant by Gnosis Builders. The prototype uses a fault-proving system and introduces strategies to manage the large amount of data required. ChainSafe plans to continue developing Zipline and aims to have a production-ready version by the end of 2023.