#!!! buster backports is needed for a lot of things
cat << EOF > /opt/chroot/$chrootdir/etc/apt/sources.list.d/buster_backports.list
deb http://deb.debian.org/debian buster-backports main
+deb-src http://deb.debian.org/debian buster-backports main
EOF
# oooo annoying, pin preferences for buster-backports