- as requested in the forum, the thumbnail provider should also work for *.FCBak file, see https://forum.freecadweb.org/viewtopic.php?f=4&t=10775&p=381936#p378680
git-svn-id: https://free-cad.svn.sourceforge.net/svnroot/free-cad/trunk@5000 e8eeb9e2-ec13-0410-a4a9-efa5cf37419d