[Mailman-Users] Confused About MIME Types

All, I am a newbe to mailman and I may ask a dumb question, sorry. I have Mailman 2.1.5 and a list working well. I would like to send an attached PDF file to members on the list. I know there is "Content Filtering" to describe the types of MIME to not allow and they must start with multipart as:

[Mailman-Users] Public vs Private Mailing List

I just installed Mailman version 2.1.5 on a Fedora Core 4 server and all seems to be working well. I created two lists, mailman and second. I marked mailman as a private list and second as a public list. When I request the public lists available by e-mail from the mailman-request address it tell