[Sinisan]

Ok. Thank you for this precision : now, I know I have to check into the log to see if it's official, and if it's "official", no help can be asked here.

No, you have to contact the people where you downloaded the LibreELEC build in the first place.

To be exact: more than 1 person or team are making their _own_ builds of the LibreELEC source code, with their _own_ set drivers, features and whatnot. You cannot ask someone to check someone else's Kodi build if there is a problem. It doesn't work that way. So yes, in case of the official beta builds go to the LibreELEC forum. Anything LibreELEC build with a full datetime, name and/or other serial number(s) added, it comes from someplace else.

FYI: LibreELEC-Generic.x86_64-9.0-Milhouse-20190112210257-%230112-g84c634a.tar is build belonging to this forum thread. That's all. 

Thank ou for your answer and precision. Now I know the thread named "LibreELEC Testbuilds for RasperryPi (Kodi 18.0)" is dedicated to Milhouse builds.

For the rest, I'll try to learn courtesy this new year.