Thank you for your response—interesting. That would be something like a 2-minus-1 road ("Kernfahrbahn" in German) which in my understanding, too, would indeed be marked as a shared lane.

These roads usually don't have a center line, though, whereas this one even has a solid one. That prevents vehicles from overtaking with a sufficient passing distance which defeats the basic idea, really.

So the marking here looks like a regular cycle lane but narrower than the law requires. So the idea is to mark them as shared lanes to differentiate them from proper bike lanes, emphasizing that they are not safe? Maybe you have a point.

Thanks again!