Unable to answer "What kind of building entrance is this?" – https://osm.org/node/842114476 via StreetComplete 57.4:

Links Eingang zur Energiezentrale. Rechts Nebeneingang der HS.

Attached photo(s):
https://westnordost.de/p/212718.jpg
https://westnordost.de/p/212719.jpg
https://westnordost.de/p/212720.jpg