Comment # 20 on bug 938659 from Johannes Meixner

I also digged in the systemd-221 sources to find documentation
about the meaning of ENV{ID_USB_INTERFACES}=="*:0701??:*".

The only non-udev-rules file where ID_USB_INTERFACES is found is
src/udev/udev-builtin-usb_id.c and therein not any helpful comment
which means one has to parse the code to find out what
ID_USB_INTERFACES contains which leads to:
-------------------------------------------------------------------------
static int dev_if_packed_info( ...
  ...
                if (snprintf(if_str, 8, ":%02x%02x%02x",
                             desc->bInterfaceClass,
                             desc->bInterfaceSubClass,
                             desc->bInterfaceProtocol) != 7)
                        continue;
-------------------------------------------------------------------------

I.e. ID_USB_INTERFACES contains a concatenation of what "lsusb -v" shows
as bInterfaceClass bInterfaceSubClass bInterfaceProtocol

FYI on my Tumbleweed system:
-------------------------------------------------------------------------
# lsusb -v -s 001:002
Bus 001 Device 002: ID 04f9:0022 Brother Industries, Ltd HL-5150D series
...
      bInterfaceClass         7 Printer
      bInterfaceSubClass      1 Printer
      bInterfaceProtocol      2 Bidirectional
...

# udevadm info -x /dev/bus/usb/001/002 \
 | egrep 'SUBSYSTEM|DEVTYPE|ID_USB_INTERFACES'
E: DEVTYPE=usb_device
E: ID_USB_INTERFACES=:070102:
E: SUBSYSTEM=usb
-------------------------------------------------------------------------