ak820-ctl controls the Ajazz (EPOMAKER) AK820 Pro keyboard on Linux,
replacing the Windows-only vendor software. It sets the 20 lighting
modes (color, rainbow, brightness, speed, direction), the sleep timer,
and syncs the system time to the keyboard's TFT clock.

Two programs are installed: the ak820-ctl command line tool and the
ak820-gui control panel.

The keyboard must be connected with the USB-C cable (USB ID 0c45:8009),
the 2.4G dongle and Bluetooth are not supported. A udev rule is
installed so the logged-in user can control it without root. Replug
the keyboard after installing.

rc.ak820-lcd runs "ak820-ctl lcd", which shows the time and CPU/GPU
temperature on the keyboard's screen. It is not enabled by default:

  chmod +x /etc/rc.d/rc.ak820-lcd
  /etc/rc.d/rc.ak820-lcd start

See the script's header to start it at boot. Errors go to syslog.