Its a bit funny that he mentions in the article that the 'key chain' is totally undocumented and has no function outside Europe...
It is used to lock the power switch in permanently on-state on the side by inserting the 'key' into the slot that comes into view when the side power switch is pushed forward which I presume is present on the US version of the saw too.
Its main use is though definitely NAINA i.e. having the Carvex upside down in the CMS-PS insert under the table and controlled with the CMS-GE/VL power switch instead of the saw's one but I wouldn't put it past woodworkers to have their own makeshift jigsaw-tables where this is a good part to have and not just toss it away as an oddment.
