I don't understand what you mean by "first principles". Open up Python's source code and check - this is first principles-first hand. As a matter of fact I am

I don't understand what you mean by "first principles". Open up Python's source code and check - this is first principles-first hand. As a matter of fact I am going to go as far as saying that reading source code is the _only_ way to actually be any good in software engineering because it's the only source of truth that never gets out of sync with the de-facto. Did you expect to find a blog post about it (you can find it on the first page of Google search I mentioned)? Or a YouTube video (didn't pay attention to that)? Books are reasonably good but usually get out of sync quite fast. And going back to first principles: the reason most of the literature may not mention what sorting algorithm Python uses is because a) it's irrelevant as a first principle knowledge b) it gets quickly out of sync.