Rover, the GraphOS local development CLI, has been improved to make it faster for developers to contribute to supergraphs using subgraph mirroring. This feature enables users to spin up a locally running supergraph in seconds by pulling down subgraph routing URLs and schemas from a GraphOS Studio variant. Subgraph mirroring reduces time spent getting up and running locally for teams maintaining supergraphs with dozens or hundreds of subgraphs, saving contributors from wasting time writing or debugging supergraph configs. The feature also allows users to quickly test subgraph changes before publishing them, making it easier to maintain a simpler supergraph config with just the subgraphs they want to override. Additionally, Rover has received quality-of-life improvements and bug fixes in its previous release, including more helpful linting messages, better support for router customizations, native Apple Silicon binaries, and several other fixes. The latest update brings Studio and Rover closer together, and Apollo is working on further improvements to the Federation contributor experience across all local development tools.