Unable to answer "What’s the surface here?" for https://osm.org/way/32150149 via StreetComplete 45.1:

Zteos are covered in non slip rubber composite looking material of some type

Attached photo(s):
https://westnordost.de/p/105746.jpg
https://westnordost.de/p/105747.jpg
https://westnordost.de/p/105748.jpg