Does Mailman have an API or list of export lists, users and owners?
it may be too late, but the list_members LISTNAME command (executed from the shell) will give you all the elements of the list.
list_admins LISTNAME will give you owners What do you mean by type of membership? List_members has the ability to filter digest vs non-digest files. I don't think there is a way to get the moderation flag without writing the script to use with the list
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This is very late too, but I've been using this script for a while to get my mailing list subscribers.
As the script says, it uses a web interface to get all members, which is quite handy since I don't have access to the mailman (shared hosting) command line tools.
As of now, this will only give you members, but you can probably expand it to suit your needs.
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There are a couple of bolts on plugins and API packages implemented in PHP. PHP Mailman Interface
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