I just skimmed through the the fido-u2f specification searching for `user verification`, however, I couldn't find what I was after. On your
demo site, there's a 'touch' argument. It's marked as 'true'.
My question is:- Is that 'touch' value signed by the u2f device? Or is that just the browser telling the the site that it requested a touch? I ask because, obviously, if malware is on your machine, the site could request a touch, but the malware could easily swap it out before it reaches the key and mark it as not-touch, then, on the way back to the site, swap it back round to being 'touched' again.
The reason why I don't think it is is because it's under the "Authentication parameters", not "Response data".