Currently the zoneinfo package is only really necessary if you want to use our zoneinfo files, which I suspect are mostly used either out of ignorance or on Windows (which does not ship zoneinfo).

Ideally, we'd have an option to install a version of dateutil without zoneinfo (no files, and without the module). I'm not really sure how to do this, however. There's the extras-require option that lets you have some sort of conditional build dependencies, but I don't know if there's a way to have "extras" that essentially take away features, rather than add them.