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