In the early 1980′s Richard M. Stallman created the GNU project, whose goal was to provide the world with a Free Operating System (with the word “Free” with the same meaning as in “Freedom”).
Since then, a lot of Free Software was developed and entire operating systems based only on Free Software were created. Unfortunately, some data is still stored in a format that is proprietary, secret and non-standard, made by corporations that want to retain control over the users of the software that generates such data.
This, of course, is meant to keep the users following the newer versions of the software that “control” the users’ data (so that the users can still have access to their own creations).
Also, unfortunately, most of the time, the software for manipulating such data is not Free in the sense desired by Richard Stallman. Software that does not allow all the freedoms stipulated by Richard Stallman is called non-free software.
The vrms program provides the facility for users of Debian-based Operating Systems (like Ubuntu Linux) to detect if their systems have any non-free software installed, so that the users can keep their computer “pure”, without non-free software.