The Bro bug/issue tracker at http://tracker.bro.org has been migrated from Trac to a JIRA instance hosted by Atlassian (you'll notice the former URL now redirects to https://bro-tracker.atlassian.net).
A couple new things that JIRA facilitates and may be interesting to try are issue "voting" and "watching." Like before, issue change notifications are always sent to the bro-dev mailing list, but users may watch specific issues and they'll also get a direct email from the tracker. Watching may also be useful for quickly finding the issues you're interested in as there's a widget to display watched issues on the dashboard. Issues can also be voted on, perhaps helping Bro developers better prioritize work according to demand.
The most significant thing users should note is that as part of the import in to JIRA, accounts have been created with the same usernames as were in Trac, however password resets need to be requested before they can be used to log in. This can be done by selecting the "Unable to access your account?" link from the log in screen to request password reset instructions via email.
Another benefit of the new tracker is that account creation is no longer "by request only," anyone can now create an account themselves. So if you've ever had an issue with Bro, but been too lazy to request a tracker account in order to file the bug report, give the new tracker a try.