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