Nicolas,

2013/12/9 Nicolas Goaziou <n.goaziou@gmail.com>

> > #+HTML_HTML5_FANCY: t
> >
> > in level-0.org
>
> There is no such keyword. Use:
>
>   #+OPTIONS: html5-fancy:t
>
> or set `org-html-html5-fancy' to a non-nil value.
>
>
Thanks. I copied that line from here:
http://orgmode.org/worg/org-tutorials/org-publish-html-tutorial.html#sec-5

I don't know of this constitutes a bug in the document using that keyword,
but that is something that misled me.