Looks like a substation to me

via StreetComplete_ee 61.1

Attached photo(s):
https://streetcomplete.app/p/296428.jpg

Unable to answer "Is there a public bicycle pump here (at least when it’s open)?" – Fahrradwerkstatt (Bicycle Shop) – osm.org/node/4926238127 via StreetComplete_ee 61.1:

Tenporaryly closed untill 18.7.

Der Weg vom Sportplatz ist bis zu den gärten als Feld/grasweg verbunden

via StreetComplete_ee 61.1

Signalanlage in Richtung Frankfurt

via StreetComplete_ee 61.1

Attached photo(s):
https://streetcomplete.app/p/291948.jpg

Signal, nach Norden gerichtet, mittig

via StreetComplete_ee 61.1

Attached photo(s):
https://streetcomplete.app/p/291946.jpg

Signal Strecke nach süden

via StreetComplete_ee 61.1

Attached photo(s):
https://streetcomplete.app/p/291944.jpg

Unable to answer "Do the trees here have needles or leaves?" – Natural Wood – osm.org/way/317035857 via StreetComplete 60.3:

Das ist eine grassfläche

Signalanlage Richtung Friedberg

via StreetComplete_ee 61.1

Attached photo(s):
https://streetcomplete.app/p/291947.jpg

Signale, nach süden zeigend

via StreetComplete_ee 61.1

Attached photo(s):
https://streetcomplete.app/p/291945.jpg