Is he that great at writing free software? There are certainly a lot of important, great, useful, projects coming out of GNU, but how much of the code has he pe

Is he that great at writing free software? There are certainly a lot of important, great, useful, projects coming out of GNU, but how much of the code has he personally had a hand in writing? I'm honestly asking because I'm not sure. I don't know if he wrote all of it himself, or none of it.