This is a part of the Beaker p2p browser project [1]. This server lets you host websites over the Dat protocol with DNS shortnames, as well as HTTPS as a fallback for (let's say) "legacy" browsers.
Happy to answer questions.
EDIT: direct link to the repo https://github.com/beakerbrowser/dathttpd. We also have Prometheus/Grafana integration which is pretty handy; it's currently the easiest way to watch the health of a swarm.