The Zope project uses the Launchpad platform for managing bugreports:
https://bugs.launchpad.net/zope2/
As an active Zope 2 committer you should be subscribed to the zope2-tracker notifications mailinglist. This list will receive notifications from the for each updated bugtracker issue.
http://mail.zope.org/mailman/listinfo/zope2-tracker
For working on bugs you need to be member of the Zope 2 developer team on Launchpad. Join the team.