If you search online, the most common method for extracting a list of subscribers of a Mailman list requires command-line access to the Mailman server. There's a much more user-friendly way to do it via the web interface.
The easiest way is to pull up the roster, which you can do by taking the web address for the admin interface, and substituting the word "roster" for the word "admin". So for example:
https://lists.mayfirst.org/mailman/admin/superfriends
Becomes:
https://lists.mayfirst.org/mailman/roster/superfriends
You can copy the list from here straight into Excel, though there are two caveats:
- There's a separate list for digest and non-digest subscribers, be sure to copy/paste both.
- I usually paste this into a text editor like Notepad before pasting into Excel, it takes out all the hyperlinks!
Then you're done, except the addresses look like:
jon at test.com
jack at example.org
I use this formula in Excel to fix that (assuming I'm pasting e-mails into column A):
=TRIM(SUBSTITUTE(A1," at ","@"))
Copy that all the way down, and you have your e-mails!