Looking for an open-source: Task, feature and issue tracker

[Alec Taylor]

Dear Python list,

Do you know of any open-source task, feature and issue trackers which
are built with Python?

Preferably with:
- git integration ("commits <> and <> solve issue/task <>"; "issue is
assigned to repo <>")
- prioritisation of tasks, features and issues
- ability to show dependencies between tasks, features and issues
- milestones; ability to link milestones with git tags; and milestone
dependencies
- Kanban boards
- Scrum (support for multiple sprints, burndown charts and backlogs)

If you don't know of any ones written in Python which cover this list;
then do you know of ones written in any language with this support?

Finally if there are no open-source projects fully covering this
feature-set; can you recommend a proprietary offering?

Thanks for all suggestions,

Alec Taylor