The online descriptions of the available issue types read:
- Epic: Created by JIRA Agile - do not edit or delete. Issue type for a big user story that needs to be broken down.
- Story: Created by JIRA Agile - do not edit or delete. Issue type for a user story.
- Bug: A problem which impairs or prevents the functions of the product.
- Improvement: An improvement or enhancement to an existing feature or task.
RFC-43 specifies more specific definitions within the context of LSST:
- Story: the result of breaking down a large task derived from the software development roadmap (LDM-240) – an epic, in other words – into workable units
- Bug: a fault or error in code which has already been accepted to master
- Improvement: a feature request or enhancement which has not been derived by breaking LDM-240 down into epics
It would be helpful if developers could see these descriptions in Jira, rather than the defaults.