juggling for recipients in headers
Original LP Author: Sumana Harihareswara , LP Link: https://bugs.launchpad.net/bugs/1414147
Strip nodup recipients from both the To and Cc headers, and juggle recipient headers so that the list address is always in the To field. This might address the other major complaint against no-reply-to-munging, recipient proliferation.
From http://wiki.mailman.psf.io/DEV/Mailman%203.0?action=diff&rev2=30&rev1=28 -- a TODO for the Mailman 3.x series.