you need to define what is leak````` whether it is a discover of detailed sensitive data, or an informal acknowledgement of its existence? For the former, it is difficult! I mean very difficult! even it was, the beneficial would be the high ends of the counterparts not the general public like us````````````but the latter one? haha, that is up to everyone's experience to filter out what is nonsense and what is the real dealH20 would appear just like J20 did. There was no news or leaks before J20's suddent appearance, which surprised United States Secretary of Defense Robert Gates during his visit to China, obviously even CIA couldn't obtain the intel to inform Gates.
H20 would be far more secretive than J20 because of its strategic value in nuclear strike capability, thus it should be at the very top of classified info level just like type 09V nuclear submarine. Anyone who leaks the news won't be just going for tea drinking, they might not be able to see their family and friends for the rest of their life time.
for the H-20 part, one of the hilarious nonsenses are that can go supersonic lol