From within the log-directory view of a Package result, or the Live Status page, you can choose to open any of the Wireshark captures for any test, on any interface. Captures files are saved with the ".cap" extension.
The first time Firefox tries to open a capture file, it will ask the user what to do. Choices will include "Open with..." and "Save to disk." Click "Open with" and navigate to the Wireshark executable. Then, check the box that says to "Do this automatically for files like this from now on" to force Firefox to open capture files every time.
You can change this back at any time from within the Firefox Preferences - Downloads section.