I'm trying to find a reason to keep this line...
SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", GROUP="usb"
in /lib/udev/rules.d/40-gentoo.rules we have inherited from older udev,
going back some time now
# find /dev -group usb -exec ls -l {} +
results nothing on every system tested
and the original /lib/udev/rules.d/50-udev-default.rules from
udev-197/198 has:
SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", MODE="0664"
which seems to be what we want?
I can remember one or two ebuilds making use of group usb, but they have
their own udev rules that makes them to do that, and are not dependant
on these rules
