Unable to answer "What’s the surface here?" for https://osm.org/way/729421009 via StreetComplete 45.1:

This is paved with large pieces of ceramic, fit together very smoothly.

Attached photo(s):
https://westnordost.de/p/104818.jpg
https://westnordost.de/p/104819.jpg
https://westnordost.de/p/104820.jpg