"Essentially it just uses Ethereum as an event log and all the computation happens inside your Urbit instead of on-chain." [1]
A more up to date version of the document shared in the google group can be found in this video [2]
- [1] https://groups.google.com/a/urbit.org/g/dev/c/p6rP_WsxLS0/m/...
- [2] https://youtu.be/CKuHXrdkIw0