The Bugzilla portlet is useful for JIRA installations whose original data came from Bugzilla, and whose users want to search for an issue by its old Bugzilla ID. They can enter the ID into the portlet text field, and will be taken to the JIRA issue. If no JIRA issue is found, they are redirected to the Bugzilla issue (eg. the bug was in a project that wasn't imported).

The bugzilla portlet is visible at http://issues.apache.org/jira/