A proposed class action in California challenges Microsoft, GitHub, and OpenAI for alleged copyright violation around GitHub Copilot, an artificial intelligence (AI) powered open source code generating assistant. The lawsuit alleges that Copilot is trained on public repositories of code extracted from the web, some of which is licensed content. While the case is in the initial stages, and the defendants will argue that their use of code qualifies as fair use under US copyright law, the outcome of this lawsuit may have significant consequences for the future of generative AI.