Hintergnommen, if it exists, would be the home of the Hintergnomes. Hintergnomes don't exist, so there's no need for a Hintergnommen, but if they did exist and did need a home, Hintergnommen would be that home. Hypothetically, it would be home to many mushrooms, as the Hintergnomes would hypothetically be excellent tenders of mushrooms, and they'd possibly even supply a solid portion of Unda's food supply. Seeing as Hintergnomes, and thus Hintergnommen, don't exist, this cannot possibly be the case.