Linux is not in the public domain. Linux is a cancer that attaches itself in an intellectual property sense to everything it touches. That's the way that the license works.
Bio: The Nag Hammadi library is a collection of Gnostic texts discovered near the Upper Egyptian town of Nag Hammadi in 1945. Thirteen leather-bound papyrus codices buried in a sealed jar were found by a local farmer named Muhammed al-Samman.