Unable to answer "Who is allowed to park here? Parking may be free or paid." – Parking Lot – https://osm.org/way/863614536 via StreetComplete_ee 59.2:

Needs to be split up; partially visitors only, partially company only, partially private

Parking slot 1,2,7,8 are company, 3,4,9,10 are generally "reserviert" (some have plates on reservation indicator), 5,6 are customer only (Klinik im Hasel), etc..., may come back to this later to fix properly