[Inkscape-user] Line reported to be longer than I expected

When I load something like this: <svg width="200mm" height="400mm" viewBox="0 0 200 400" version="1.1"> <g fill="none" stroke="black" stroke-width="2" > <line x1="1" y1="0" x2="1" y2="400" /> </g> </svg> The line is reported to be 2mm longer than I expected (402mm), even though it touches the bottom and top of the page perfectly, the page is reported to be exactly 400mm high. Is this a bug or a feature?