It seems to show all flights available in that fare class, at least the ones with logical routings. For example on a HKG-FWA leg I got the daily HKG-DTW flight coupled with each of the daily flights available DTW-FWA, plus one HKG-NRT-DTW-FWA possibility for each DTW-FWA flight, plus one HKG-NRT-MSP-FWA possibility for each MSP-FWA flight, which are the only routings that really make sense, though others are possible without an overnight (HKG-NRT-ATL-FWA for example). But since the fare class isn't shown when picking the legs, I can't tell if it is displaying any legs in higher fare classes. It doesn't seem to be.