Comment 1 for bug 168753

Originator: NO

Additional to this - Inkscape also converts pt to px in font-size: section
of style attributes in text elements.

I have written a console app to fix the SVG files, but I would really
prefer if Inkscape didn't convert in the first place.

Note: On re-opening an SVG with mm dimensions and re-saving, inkscape
respects the units unless the element had been changed during the session -
then it's back to "user units" (pixels) for that element.