Except the Linux Kernel technically does have a code of conduct, it's just called the Code of Conflict, and while it basically states they'll deal with problems

Except the Linux Kernel technically does have a code of conduct, it's just called the Code of Conflict, and while it basically states they'll deal with problems on a case-by-case basis, it does explicitly give people a way to air their grievances and attempt to have problems addressed. Additionally, while C itself doesn't have a specific code of conduct, the International Standards Organization (which C belongs to and is governed by) has a code of conduct and code of ethics.