The source code powering git-send-email.io.
git-send-email.io into the subject line:
git config format.subjectPrefix 'PATCH git-send-email.io'
and send patches to ~email@example.com.
To run the website, just serve this directory as static content with your favorite httpd. Here's a one-liner:
python3 -m http.server 8000
Running the auto-responder... is much harder. This depends on a fully operational lists.sr.ht setup, which requires at least 5 daemons and a working MTA. This is left as an exercise to the reader. Rig up a webhook to receive post:received events from your test list to /webhook.