Unable to answer "What are the opening hours here?" – Servicetorget (Government Office) – https://osm.org/way/107817037 via StreetComplete 59.0:

Contrary to their name, they have moved to Nedre Rommen 5, 0988 Oslo. GMaps link: https://maps.app.goo.gl/NhntztnQnB19v1Zw9