Where does the name "zero type" come from? In type theory this is called an "empty" type because the set of values of this type is empty and I couldn't find (though I have no idea where to start) mention of it as a "zero" type.

This stuff is foundational and so it's certainly a priority to get it right (which C++ didn't and will be paying for until it finally collapses under its own weight) but it's easier to follow as an outsider when people use conventional terminology.