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.
The PNM file type is primarily associated with PBM Portable Any Map Graphic. A family of formats. The files are usually .PNM but can have the form .P?M with ? being any letter.