Fair point, and you're right. On iOS the stock font set is essentially uniform across devices in the same OS version, so the "nearly unique" claim doesn't hold there. Just pushed a hedge: prose now distinguishes between desktop (where fonts accumulate via apps and OS over time, and the bundle is genuinely identifying) and iOS/Android (where it isn't, on its own). Combined with screen + GPU + language + timezone the iOS version still narrows the field, but the prose shouldn't overclaim. Thanks.