Short description of error
SVG files with viewBox attribute that differ from with/height attributes are scaled wrong.
Exact steps for others to reproduce the error
Cteate SVG file with content below:
<svg width="1000mm" height="1000mm" viewBox="0 0 1 1"> <g> <path d=" M 0.0, 0.0 L 1.0, 0.0 L 1.0, 1.0 L 0.0, 1.0 C "/> </g> </svg>
And then import it with File -> Import -> Scalable Vector Graphics (.svg). It is expected that the square will be 1x1 Blender units, but it's 3543x3543 Blender units.
That is because scaling is performed twice in SVGMatrixFromNode() function in import_svg.py file.
I don't quite understand what's happening during the function and why first scaling is needed, but I've made a "patch" that, I believe, kinda solves the issue. I may be totally wrong with this solution =)