note that for example this specific hydrant will not have a pillar, but will look like this https://wiki.openstreetmap.org/wiki/File:Berlin_hydrant_20050211_p1000517.jpg (I think that SC show matching imagery) and may be for example on the road.

Also, it was mapped 10 years ago and this road was rebuild since then - so maybe it is actually gone?

BTW, in case of leaving notes adding photos helps (sometimes info can be spotted even if photographer missed it, it also confirms that mapper was there raising how trustworthy notes are)

BTW, I hope that SC is useful and Kraków is nice and you had fun and/or accomplished what you were trying to do!

(I am one of contributors to SC and live in Kraków)