We propose, in this issue to implement a IsFromMailingList matcher, in the mailet/standard project.
This matcher will return recipients of the mail if we have good reasons to think the mail is from a mailing list.
You can rely on the AutomaticallySentMailDetector::isMailingList utility.
You will introduce unit tests & class javadoc for your matcher.
If you want to handle this issue, and need guidance, please reach us on Gitter: https://gitter.im/apache/james-project