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