I couldn't really help myself, I know it is a really small thing but kind of cool.
If you flip the magnetic foot of a clip and park it on the etched circle it connects to the metal base. Then there is another etched spot (the oval) with bare metal where you can feed, ground or measure the connected clips potential (see picture).
The clip is only connected to the base material when the magnetic foot is positioned "upside down" in "normal position" it is isolated from the Base.