It seems we need some tutorial for German tram signals... They are way more complicated than our 4 dot signals.
https://commons.m.wikimedia.or…vo.jpg#mw-jump-to-license
In Prague we got usually this. The two dots are part of the 4 dot signal, the red arrows signal switch position. There is sometimes also small yellow box with \|/ arrows. It can be seen also at bus intersections and signals traffic lights' preferention of public transport vehicle.