@OlivierQC thanks for these pictures.

Gives a good overview but not detailed/focused enough to read the text/codes on the individual components.
DC Power capacitor, PSU's section, DAC+Clock circuitry, XLR AMP left/right and RCA AMP sections are neatly marked. It is a nicely build board with looks like a quality design for AMP's and the audio panel secondary power. Power for it is derived from the main switched mode PSU for the SOC + HDD's. Can't judge the individual component quality used for this design (yet).
I think it uses I2S interfacing with the SOC main board and not an internal USB port as I don't see components for that. That explains it is not seen by APP's designed for USB DAC's. Makes sense to me too as this interface is a lot simpler to implement. The information I got earlier from Zidoo using internal USB for interfacing is most likely erroneous. This just means deployment of the SABRE audio chip will depend on the APP's provided by Zidoo.
If you could do one more it would be nice. Please take a full top view with just the audio panel on it. Should be sharp overall and as high res as possible.
Updated my review:
https://www.futeko.com/newforum/index.php?topic=3868.0
This for honest comparison with the DIY-kit with the details further revealed.
The panels potential sound quality should be close HW wise. It all depends on the Audio APP's provided how functional it will become. Seen questions asked by Zidoo work seems to be in progress to make further steps there. This specifically for playing SACD originated audio files.