hackthemap
Unable to answer "What diameter is specified on the sign for this fire hydrant?" for https://osm.org/node/8582590415 via StreetComplete 38.2:

No sign, photos of the above ground fire hydrant attached

Attached photo(s):
https://westnordost.de/p/73583.jpg
https://westnordost.de/p/73584.jpg
https://westnordost.de/p/73585.jpg
https://westnordost.de/p/73586.jpg
https://westnordost.de/p/73587.jpg