This documentation explains how to use Yubikeys based on a dedicated USB VM. However, a sys-usb does not always exist. Which other qubes, handle USB devices when sys-usb is not specifically allocated during installation?
The intentation is to solely perform 2FA with it. Which drivers have to be installed then?
If sys-usb does not exist then sys-net is normally handling the usb functions. Further specific reading about yubikey can be found in the documentation.