This guide explains how to export mailing list subscribers through the Mailman web interface or by email.
Access to the subscriber list depends on the your list settings.
If you are a member, moderator, or owner of a mailing list:

Compose an email message to the request address of your list.
Your request address should be: listname-request@lists.mayfirst.org
Replace "listname" with your actual listname followed by your list domain.
For example if your if your list address is special@lists.mayfirst.org then your request address would be special-request@lists.mayfirst.org
In the the subject line of this email write only:
who