Und in der englischen Version steht nichts von Hydranten:

The key object:= was used by several mechanical edits in Germany in 2015 and afterward, to add address information to small man-made features such as lamp posts and memorials, which had no address (addr:=) that was given out by officials. The subkeys use the Karlsruher Schema. The main feature tags used were public artworks, memorials, control boxes for traffic light- and telecommunication systems which were not assigned an address, but near to an object having an official address tagged with addr:=.

Wiki-Quelle: Key:object:*

Mit dem were klingt es für mich, als würde man es heute nicht mehr nutzen. Also falls jemand Lust hat, die englische Version an die deutsche anzupassen…