How we got the numbers
Distance and climb come from the line itself: heights from the Copernicus GLO-30 elevation model (30 m), sampled every 30 m and smoothed with a running median of five samples, because in forest the model measures the top of the trees, and climbing counted once the height has changed by 3 m. These are the figures the app shows. Expect them to differ from a GPS track by 10 % or so.
Walking time follows the DIN 33466 rule used by the German and Austrian alpine clubs, without breaks. Difficulty comes from the whole outing (there and back): the climb and that time, one level up when 30 % or more of the line is on slopes over 30°.
4 % of the line itself runs on slopes over 30° in the elevation model; slopes above it are not counted. This describes the terrain, not today’s conditions, and it is not an avalanche rating.