Calling

Perms::get(array('type' = 'trackeritem', 'object' = ID))

will return permissions in this order:

1. TrackerItem Object permissions (if any).

2. TrackerItem Category permissions (if item is categorized and
permissions are available)

3. Parent Tracker Object permissions (if any).

4. Parent Tracker Category permissions (if tracker is categorized and
there are any permissions)

5. Global permissions.