Create a foobar repository:
apt-get install reprepro
OUTPUT=$(mktemp -d)
mkdir -p $OUTPUT/conf
cat > $OUTPUT/conf/distributions <<CONF
Codename: foobar
Components: main
Architectures: amd64
CONF
reprepro -b $OUTPUT includedeb foobar path/to/*.deb
rm -fr $OUTPUT/{db,conf}
aws s3 sync --acl public-read $OUTPUT/ s3://BUCKET/debian/buster/To use it:
echo 'deb [trusted=yes] https://BUCKET.s3.amazonaws.com/debian/buster foobar main' \
> /etc/apt/sources.list.d/foobar.list
apt-get update
apt-get install ...