1 deb http://deb.debian.org/debian bullseye main contrib non-free
2 deb http://security.debian.org/debian-security bullseye-security main contrib non-free
3 deb http://deb.debian.org/debian bullseye-updates main contrib non-free
4 deb http://ftp.debian.org/debian bullseye-backports main contrib non-free