See mockup on Figma: https://www.figma.com/proto/RaBL0FL199pbWkh7TUJXIrAP/Trackers-service-flow?node-id=39%3A492&scaling=scale-down&redirected=1

The breadcrumb will display a list of other trackers in the project.
The list is limited to 10 or 15 entries (depending on what is possible to show on a screen of a reasonable size, for example a laptop).
The list of trackers is sorted by lexicographical order.
Test executions are excluded from the list. They are a special tracker and people rarely, if ever, need to access them directly instead of through Test management.

Notes:

There were other ideas proposed for the tracker "selection" and sort :

1. Marking trackers as "favorite" or "starred" and showing "starred" trackers. It was not kept because it requires the Tracker administrators to classify trackers. If they don't, it changes nothing on the tracker user's experience.
2. Sorting by "last modified date". It raises concerns because this sort will vary a lot and weighs in favor of "Tasks" trackers or "Test Execution" trackers, which have intensive use and are not necessarily relevant to access directly. Tasks are more accessed through Cardwall for example.