Comment # 10 on bug 1174406 from Robin Klitscher

For whatever it may be worth, my setup in Leap 15.2 as host with Win10 as guest
in VB 6.1.12_SUSEr139181 has a 60-vboxdrv.rules file in usr/lib/udev/rules.d/,
but not in /etc/udev/rules.d/

Copying the 60-vboxdrv.rules file from the former into the latter with the
given lines uncommented (they weren't commented anyway) made no difference -
still no USB in the VM.  

(An oddity is that the USB mouse and keyboard both work in the VM, but no other
USB device is detected even though they exist)