Email auto-discovery means a client email is able to automagically find out about what ports and security options to use, based on the mail server URL. It can help simplify the tedious / confusing task of adding own's email account for non-tech savvy users.

Basically, email clients will search for auto-discoverable settings and prefill almost everything when a user enters its email address :heart:

There exists [docker-email-autodiscover](https://hub.docker.com/r/jsmitsnl/docker-email-autodiscover/) on hub.docker.com but the upstream project is actually gone from GitHub. There are some forks available though.