deb      http://ftp.de.debian.org./debian             buster                  main contrib non-free
deb      http://ftp.de.debian.org./debian             buster-updates          main contrib non-free
deb      http://ftp.de.debian.org./debian             buster-proposed-updates main contrib non-free
deb      http://security.debian.org./debian-security  buster/updates          main contrib non-free
deb      http://ftp.de.debian.org./debian             buster-backports        main contrib non-free
# deb      http://ftp.de.debian.org./debian             buster-backports-sloppy main contrib non-free