https://www.mutt.org/: valid certificate, redirect, default

Currently, the main project website seems to be http://www.mutt.org/. The server also supports https://www.mutt.org/, but the certificate is only valid for "*.cass.oregonstate.edu".

It would be awesome to convince the hoster https://osuosl.org/ to set-up Lets Encrypt certificates for all VHosts on their server.

As a next step, it would be great to have HTTP redirect to HTTPS.

Finally, https://www.mutt.org/ should become the default webseite in all documentation.