Several ways in the Project panel.
In a related vein, if you're working in the Timeline and want to find the project item that a track item is from, right-click and select "Reveal in Project." As of CC, the same feature is available for finding the sequence by right-clicking the sequence's tab.
Also new to CC, PPRO has duplicate frame markers that indicate if the same segment of a clip has been used more than once. You enable this through the Timeline Display Menu accessed via the wrench icon near the upper left corner of the Timeline panel.
More info than you asked for, but no extra charge ;-)