Interesting... frames, of course, are not included in the html 5 spec, but they are still included in NoF 2013, I guess because you still have the choice of outputting html 4. However, when you select 'generate autoframes' in the masterborder properties palette, NoF happily lets you do so giving the impression that it is going to, in fact, generate frames even though html 5 output is selected.

However, when you look at the generated code, there are no framesets generated (which is a Good Thing IMHO). Maybe a dialog pop-up saying something like, 'html 5 output selected; frames deactivated' could be generated when somebody selects 'generate autoframes' with html 5 selected. Otherwise they might Get A Shock when they see their web site sans frames.