The corona warn app risk level calculation is parameterized by the RKI, the app downloads this parameters regularly. They are 5 or 6 parameters that define what signal strength and duration of exposures is considered a risk. All are transmitted using protobufs. I would be nice if this parametrization could be plotted as well and be able to see how this correlates with uploaded diagnosis keys over time.
I was planning to do this myself, but did not get to it up to now. Maybe you are interested in doing it.