atypical@cloud-vps:~$ apt-file search fullchain
python-certbot: /usr/lib/python2.7/dist-packages/certbot/tests/testdata/sample-archive/fullchain1.pem
python3-certbot: /usr/lib/python3/dist-packages/certbot/tests/testdata/cert_fullchain_2048.pem
python3-certbot: /usr/lib/python3/dist-packages/certbot/tests/testdata/sample-archive/fullchain1.pem