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