A Gubel is a "half-cave". The Wissengubel near Gibswil is known. Here I happened to discover a very similar Gubel that is not marked on the map. This cave is also impressive, with a small waterfall flowing over it and now with ice at the bottom. The narrow hiking trail down to the Gubel is blocked after a few meters by a fallen tree uprooted.
According to my research, *Gubel" is a hill or a rise, but not a cave. But of course, a Gubel can also have a waterfall slightly downstream or emerging from the hill. According to the map, the cave in question is called Batzberghöhle, near the Gubelbächli.