People,
as a general rule I find it rude to send attachments to mailing lists. It wastes bandwidth for both the mailing list and the subscribers, and it wastes storage for the subscribers.
More specifically; please don't send RAR archives to the RoundCube mailing lists. About one quarter of our subscribers are subscribed from Gmail addresses, and Gmail rejects RAR archives in e-mail. I learned this the hard way; having to handle more then a hundred bounces from just one list message...
The best policy is of course not to send attachments to mailing lists at all, but instead uploading the file(s) to a web server, and including a link in your message.
Bob (list administrator)