Unable to answer "What’s the surface here?" for https://osm.org/way/91059371 via StreetComplete 53.2:

Unclear how to tag this type of surface. The stones are natural and form a rough, flat-ish surface.
The same surface is used for all patha theough this small park.

Attached photo(s):
https://westnordost.de/p/161452.jpg