deb http://mirror.yandex.ru/debian/ buster main contrib non-free
deb-src http://mirror.yandex.ru/debian/ buster main contrib non-free

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

# stretch-updates, previously known as 'volatile'
deb http://mirror.yandex.ru/debian/ buster-updates main contrib non-free
deb-src http://mirror.yandex.ru/debian/ buster-updates main contrib non-free