i
mkdir -p ~/pg-client11-buster && cd ~/pg-client11-buster

echo "deb http://deb.debian.org/debian buster main" > buster.list

pt-get -o Dir::Etc::sourcelist="$PWD/buster.list" \
        -o Dir::Etc::sourceparts="-" \
        -o Debug::NoLocking=true \
        -o Dir::Cache::archives="$PWD/archives" \
        -o Dir::State="$PWD/state" \
        update

apt-get -o Dir::Etc::sourcelist="$PWD/buster.list" \
        -o Dir::Etc::sourceparts="-" \
        -o Debug::NoLocking=true \
        -o Dir::Cache::archives="$PWD/archives" \
        -o Dir::State="$PWD/state" \
        -d install postgresql-client-11

scp archives/*.deb user@debian10:/tmp/


cd /tmp
sudo dpkg -i *.deb
sudo apt-get install -f  # Fix unresolved dependencies if needed