Hi!
I've created the attached patch to disable the project prefix in notification mails because I'm a user of the common-lisp.net site which uses Trac for bug tracking for hosted projects which choose to do so.
All lists get a list prefix prepended by Mailman, so that all tickets lists have a double prefix: both mailman and trac prepend a prefix containing the project name.
If this could be turned off in Trac, there wouldn't be a need to change per-list settings in Mailman, so, I submit this patch hoping it (or a variant) will get committed.
bye,
Erik.