A low-traffic mailing list which the Shibboleth team uses to announce new releases, security announcement, and events.
A medium-traffic mailing list where users of the Shibboleth software can their deployment of the software and ask questions of the larger user community.
A low-traffic mailing list where individuals developing plugins for, or otherwise extending, the Shibboleth or OpenSAML products can ask questions. NOTE: this is not the place to ask "how do I use Shibboleth" questions. Use the users list for that.