When you visit:
https://mail.wikipedia.org/mailman/listinfo/wikitech-l
it provides the cert for *.wikimedia.org
Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=68553
https://rt.wikimedia.org/Ticket/Display.html?id=6981
https://bugzilla.wikimedia.org/show_bug.cgi?id=73290