> I see that the value is also available in the iD editor, and you may want to consult that editor for more information

note that it is coming from top used values on taginfo and it is not reviewed or intentionally added

> Based on what I've seen elsewhere, it also most likely resembles the main picture here: 

then it mismatches description on wiki of bicycle_parking=anchors ("A mere anchor hammered into a wall, the ground, or boulders. Low security.") and is again case of this tag being used where no such object exists.