Bug was first isolated thanks to the german FreeCAD contingent in https://forum.freecadweb.org/viewtopic.php?f=13&t=27344
Example SVGs are available in the ticketWith the change from 0.91 to 0.92 inkscape devs changed the conversion factor of userunit (uu) and mm. Pre-0.92 it was 1uu=1 inch/90 and starting from 0.92 it is 1 uu=1inch/96. This was necessary to meet the actual recommendations/rules of svg-standard and css. See article in inkscapewiki for further reading.
When a user creates a file in inkscape with absolute dimensions (mm) and saves it, then imports it into FC, bodies in Freecad come out with too large dimensions. For example - a 100mm square will be 106,66mm in FC now (100 x 96/90).