This format is used for data exchange in programs that work with vector graphics from Corel, and also for printing completed designs. It contains image data and also the metadata that describes it. In CMX it’s possible to store layers that can be independently edited. The format is recognized by Adobe Illustrator versions 6-8.
SK files are vector files, used by the free vector graphics editor Sketch or Skencil. The software is released under the GNU Lesser General Public License.