reference To Tracker
Filter the work items by the upstream references. Each work item is a part of the result set, which refers to an item of the specified tracker or tracker type.
For example: Bug 1 -> User Story 1
Available operators: =, !=, IN, NOT IN
referenceToTracker = 'User Story'
referenceToTracker = '5.8970'// '<projedtId.trackerId>'
referenceToTracker = 8970// trackerId since 9.0.0