Just look at the headers of the list mails:

List-Id: Rockbox <rockbox.cool.haxx.se>
List-Unsubscribe: <http://cool.haxx.se/cgi-bin/mailman/listinfo/rockbox>,
        <mailto:rockbox-request@cool.haxx.se?subject=unsubscribe>
List-Archive: <http://cool.haxx.se/pipermail/rockbox>
List-Post: <mailto:rockbox@cool.haxx.se>
List-Help: <mailto:rockbox-request@cool.haxx.se?subject=help>
List-Subscribe: <http://cool.haxx.se/cgi-bin/mailman/listinfo/rockbox>,
        <mailto:rockbox-request@cool.haxx.se?subject=subscribe>
Sender: rockbox-bounces@cool.haxx.se
Errors-To: rockbox-bounces@cool.haxx.se
Received on Mon Apr 24 11:20:37 2006