deb http://httpredir.debian.org/debian stretch main contrib non-free
#deb-src http://httpredir.debian.org/debian stretch main contrib non-free

deb http://httpredir.debian.org/debian stretch-updates main contrib non-free
#deb-src http://httpredir.debian.org/debian stretch-updates main contrib non-fr$

deb http://httpredir.debian.org/debian stretch-backports main contrib non-free
#deb-src http://httpredir.debian.org/debian stretch-backports main contrib non-$

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