/etc/apt/sources.list
# 

# deb cdrom:[Debian GNU/Linux 10.10.0 _Buster_ - Official amd64 NETINST 20210619-16:11]/ buster main contrib non-free

#deb cdrom:[Debian GNU/Linux 10.10.0 _Buster_ - Official amd64 NETINST 20210619-16:11]/ buster main contrib non-free

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

# 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 contrib non-free

# This system was installed using small removable media
# (e.g. netinst, live or single CD). The matching "deb cdrom"
# entries were disabled at the end of the installation process.
# For information about how to configure apt package sources,
# see the sources.list(5) manual.