root@jan /etc/udev/rules.d # udevinfo -a -p /sys/class/input/event16
looking at parent device '/devices/pci0000:00/0000:00:13.2/usb3/3-2/3-2.7/3-2.7.3':
    KERNELS=="3-2.7.3"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{product}=="Apple Extended USB Keyboard"
    ATTRS{manufacturer}=="Mitsumi Electric"
    ATTRS{quirks}=="0x0"
    ATTRS{maxchild}=="0"
    ATTRS{version}==" 1.10"
    ATTRS{devnum}=="26"
    ATTRS{busnum}=="3"
    ATTRS{speed}=="12"
    ATTRS{bMaxPacketSize0}=="8"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bcdDevice}=="0410"
    ATTRS{idProduct}=="020c"
    ATTRS{idVendor}=="05ac"
    ATTRS{bMaxPower}==" 50mA"
    ATTRS{bmAttributes}=="a0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bNumInterfaces}==" 2"
    ATTRS{configuration}==""
    ATTRS{dev}=="189:281"

  looking at parent device '/devices/pci0000:00/0000:00:13.2/usb3/3-2/3-2.7':
    KERNELS=="3-2.7"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{product}=="Hub in Apple Extended USB Keyboard"
    ATTRS{manufacturer}=="Mitsumi Electric"
    ATTRS{quirks}=="0x0"
    ATTRS{maxchild}=="3"
    ATTRS{version}==" 1.10"
    ATTRS{devnum}=="25"
    ATTRS{busnum}=="3"
    ATTRS{speed}=="12"
    ATTRS{bMaxPacketSize0}=="8"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceClass}=="09"
    ATTRS{bcdDevice}=="0410"
    ATTRS{idProduct}=="1003"
    ATTRS{idVendor}=="05ac"
    ATTRS{bMaxPower}==" 50mA"
    ATTRS{bmAttributes}=="a0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{configuration}==""
    ATTRS{dev}=="189:280"


root@jan /etc/udev/rules.d # cat 25-usbkeyboard.rules 
ACTION=="add", ATTRS{idProduct}=="1003", ATTRS{idVendor}=="05ac", RUN+="/usr/bin/numlockx on"
ACTION=="remove", ATTRS{idProduct}=="1003", ATTRS{idVendor}=="05ac", RUN+="/usr/bin/numlockx off"


root@jan /etc/udev/rules.d # udevtrigger --verbose --subsystem-match=input
[...]
/devices/pci0000:00/0000:00:13.2/usb3/3-2/3-2.7/3-2.7.3/3-2.7.3:1.0/input/input26
/devices/pci0000:00/0000:00:13.2/usb3/3-2/3-2.7/3-2.7.3/3-2.7.3:1.0/input/input26/event16
/devices/pci0000:00/0000:00:13.2/usb3/3-2/3-2.7/3-2.7.3/3-2.7.3:1.1/input/input27
/devices/pci0000:00/0000:00:13.2/usb3/3-2/3-2.7/3-2.7.3/3-2.7.3:1.1/input/input27/event17


root@jan /etc/udev/rules.d # udevtest /dev/input/event16 
This program is for debugging only, it does not run any program,
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.

parse_file: reading '/etc/udev/rules.d/25-usbkeyboard.rules' as rules file
parse_file: reading '/etc/udev/rules.d/53-sane.rules' as rules file
parse_file: reading '/etc/udev/rules.d/54-gphoto.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-cdrom_id.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-pcmcia.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-persistent-storage-tape.rules' as rules file
parse_file: reading '/etc/udev/rules.d/90-hal.rules' as rules file
parse_file: reading '/etc/udev/rules.d/99-fuse.rules' as rules file
parse_file: reading '/etc/udev/rules.d/bluetooth.rules' as rules file
parse_file: reading '/etc/udev/rules.d/device-mapper.rules' as rules file
parse_file: reading '/etc/udev/rules.d/udev.rules' as rules file
unable to open device '/dev/input/event16'