Medium-priority template and page issues

Maintenance categories tracking group maintenance tasks, such as ensuring all of our media articles have appropriately sourced release dates and timeline placements. These are large-scale tasks that should be fixed if you see them, but are not caused by urgent template or page issues.

When a project category is completed, it can be moved to Category:High-priority template and page issues/Empty, and the hiddencat flag removed so that any future issues will be caught.