Terminal commands show there is no non-free software on the system

vrms returns "No non-free or contrib packages installed on Hostname! rms would be proud." and dpkg-query -W -f='${Section}\t${Package}\n' | grep ^non-free returns nothing on the terminal. However, after running packages=dpkg --get-selections | awk '{ print $1 }' | sed 's/:amd64//' for package in $packages; do echo ">> "; cat /usr/share/doc/$package/copyright; done > ./licenses I see an output as following, which says there is no license for some packages: cat: /usr/share/doc/libddccontrol0/copyright: No such file or directory cat: /usr/share/doc/linux-image-4.19.0-12-amd64/copyright: No such file or directory cat: /usr/share/doc/live-tools/copyright: No such file or directory cat: /usr/share/doc/rsync/copyright: No such file or directory cat: /usr/share/doc/user-setup/copyright: No such file or directory How and commands decide they are also free in this case?