I just saw what I think is the first successful mtb decent of “the sea of rock” (may just be calling it that in the video) Mt. Sommerstein in Berchtesgaden, Germany.
It looks like they often intentionally often went off trail to make it more ‘interesting’.
The “trail” doesn’t look extreme, but you’d definately need to be an expert at Muni, since much of it is rough, there are many times that the trail disappears, significant trialsy spots, and sometimes runs along large cliffs.
No intention of me ever doing this. I don’t and doubt I’d ever have the needed skill, let alone at altitude (2308m or 7532 ft). I just remember seeing riders like Lutz riding town peaks like this and thought it’d be cool.