That is "Give tuner device status", you can't do much with that I'm afraid.
A shame,"Give tuner device status" in my case is send in stable enough manner that it could be used for enabling standby.
Sending HDMI-CEC commands from CLI? - [EN] Enduser support - Forums (openpli.org)
cec-cl may be an solution but considering I don't have that much time for it, I will go for easy solution and bind standby to red button an manually go to standby.
That explain why it's so hard to set up, there's nothing to set up on this box. You wouldn't happen to know of a way to transcode OpenWebif streams on self hosted server?