Much of the software that we encounter on a daily basis, including the bulk of the infrastructure on which the internet runs, is grounded in a decades-old paradigm called “Free and Open Source Software.” FOSS developers distribute their work under permissive licenses that allow others to use, share, modify and redistribute the resulting code for free. LLM use threatens that paradigm, in part by unleashing a deluge of difficult-to-evaluate, vibe-coded contributions, but perhaps more critically, by eroding FOSS’s social component.