Board outline with KiCAD - where is the PCB cut on the line?

I use KiCAD for PCB design and for board outline KiCAD uses a line approximately 0.4mm wide and puts it on a separate Gerber layer.

My question is that when cutting the boards, will the cut be on the inside, outside or centre of the line?

Also, what width\amount of material is typically removed when cutting? Is it more or less than 0.4mm?

I use KiCAD also. Manufacturers typically Will manufacture the PCB to the size of the center of the outline regardless of how thick or thin it is. The Seeed Studio manufacturer typically uses a router head of 2mm in diameter. So do not try to design a notch in your PCB of less than 2mm.

Thanks for that!

So I take it then the center of the line will be cut with a 2mm wide bit, resulting in 1mm loss either side of the boundary line?

The reason I ask is that I am designing a board which needs to fit into a card edge slot connector (similar to a PCI card slot etc) and the board must be a precise width so it fits into the connector without being able to move and potentially allow the contacts to become mis-aligned.