Alyssa Rosenzweig looks at getting the Exposure Notifications System protocol, developed by Apple and Google for facilitating COVID-19 contact tracing on Android and iOS phones, running on GNU/Linux. "All in all, we end up with a Linux implementation of Exposure Notifications functional in Ontario, Canada. What’s next? Perhaps supporting contact tracing systems elsewhere in the world – patches welcome." The source code for liben is available "for any one who dares go near".