Contributions must not include content generated by large language models or other probabilistic tools, including but not limited to Copilot or ChatGPT. This policy covers code, documentation, pull requests, issues, comments, and any other contributions to the Servo project.

A web browser engine is built to run in hostile execution environments, so all code must take into account potential security issues. Contributors play a large role in considering these issues when creating contributions, something that we cannot trust an AI tool to do.

— Contributing to Servo (via Simon Willison)

Critical projects should be more explicit about their policies. If I had a critical piece of software, I would do the same choice, for safety. The advantage of LLMs are not that huge to be worth the risk.