Stefan Bauer via Mailman-Users writes:
is there a way to display all list members on the list overview page?
Not on that page itself.
If you are the list owner (or site owner), on the List Identity page in List Settings, you can set Members List Visibility to moderators only, to mailing list members (it says "only" but I'm pretty sure moderators can see the list membership too), or to anyone.
In each case there will be a "Users" link on the List Overview page for folks who are allowed to see the membership.
It is generally not a good idea to set it to anyone, as the "anyones" most interested in your list membership are spammers. Also, people sometimes set their display names to embarrassing or somewhat private things, that they wouldn't use if they thought the whole list could see it. Whether there is a risk or how much risk you want to take is for you to judge, of course. That's just the generic case.
Steve