For various reasons, people do not want others to assume their hand-written code is actually written by an agent. At some level there’s an implication that hand-written code is higher quality, but there’s also some pride in saying “I made this”.
The trap is that writing bad code is a marker that a human wrote it. If you have git commits with partially-implemented features and bad commit messages it’s probably written by a person. If you write code by hand you have an incentive to leave around these human markers if only to point to them with pride at your own fallibility.