This is a clone of VRMS (Virtual Richard M. Stallman) for Gentoo Linux. It scans the computer for non-free packages, and shows a list of them, if any.
Instead of using its own list of licenses, it scans the license_group file in the local computer and compares the locally installed packages to the @FREE group. If you want it to use only the @FSF-APPROVED group you can use the --strict flag.