+ + When you are listed explicitly in the To: or Cc: headers + of a list message, or a message is sent to multiple lists + that you are a member of, you can opt to not receive another + copy from the mailing list. Select Yes to avoid + receiving duplicate copies from the mailing list; select + No to receive duplicate copies. + +
If the list has per-message personalization + enabled, every duplicate mail will have a + X-Mailman-Duplicate: yes header added to it. + +
+