/usr/share/openscad/testdata/dxf/ is in openscad-testing-data 2014.03+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/openscad/testdata/dxf/arc.dxf
/usr/share/openscad/testdata/dxf/circle-advanced.dxf
/usr/share/openscad/testdata/dxf/circle-double.dxf
/usr/share/openscad/testdata/dxf/circle-small.dxf
/usr/share/openscad/testdata/dxf/circle.dxf
/usr/share/openscad/testdata/dxf/ellipse-arc-rot.dxf
/usr/share/openscad/testdata/dxf/ellipse-arc.dxf
/usr/share/openscad/testdata/dxf/ellipse-reverse.dxf
/usr/share/openscad/testdata/dxf/ellipse-rot.dxf
/usr/share/openscad/testdata/dxf/ellipse.dxf
/usr/share/openscad/testdata/dxf/lwpolyline-closed.dxf
/usr/share/openscad/testdata/dxf/lwpolyline.dxf
/usr/share/openscad/testdata/dxf/lwpolyline2.dxf
/usr/share/openscad/testdata/dxf/multiple-layers.dxf
/usr/share/openscad/testdata/dxf/nothing-decimal-comma-separated.dxf
/usr/share/openscad/testdata/dxf/null-polygons.dxf
/usr/share/openscad/testdata/dxf/open-polyline.dxf
/usr/share/openscad/testdata/dxf/polygon-concave-hole.dxf
/usr/share/openscad/testdata/dxf/polygon-concave-simple.dxf
/usr/share/openscad/testdata/dxf/polygon-concave.dxf
/usr/share/openscad/testdata/dxf/polygon-holes-touch.dxf
/usr/share/openscad/testdata/dxf/polygon-intersect.dxf
/usr/share/openscad/testdata/dxf/polygon-many-holes.dxf
/usr/share/openscad/testdata/dxf/polygon-mesh.dxf
/usr/share/openscad/testdata/dxf/polygon-overlap.dxf
/usr/share/openscad/testdata/dxf/polygon-riser.dxf
/usr/share/openscad/testdata/dxf/polygon-self-intersect.dxf
/usr/share/openscad/testdata/dxf/polygon8.dxf
/usr/share/openscad/testdata/dxf/polygons.dxf
/usr/share/openscad/testdata/dxf/transform-insert.dxf
/usr/share/openscad/testdata/dxf/triangle-with-duplicate-vertex.dxf