That's a reference to clean room design - you don't want to be accused of stealing a competitor's design, so anyone with knowledge of that design is considered

That's a reference to clean room design - you don't want to be accused of stealing a competitor's design, so anyone with knowledge of that design is considered "tainted" and not allowed to work on your core systems ("kernel"). https://en.wikipedia.org/wiki/Clean_room_design https://en.wikipedia.org/wiki/Clean_room_design