Os dejo mi source.list para Debian 10

deb http://deb.debian.org/debian/ buster main contrib non-free

#deb-src http://deb.debian.org/debian/ buster main

deb http://security.debian.org/debian-security buster/updates main

#deb-src http://security.debian.org/debian-security buster/updates main

# buster-updates, previously known as ‘volatile’

deb http://deb.debian.org/debian/ buster-updates main contrib non-free

#deb-src http://deb.debian.org/debian/ buster-updates main

deb http://deb.debian.org/debian/ buster-backports main contrib non-free

Eso es todo :)