The Web fonts spec looks very complete. Good work!
I wonder, though, if it has to be so explicitly tied to CSS. If XML's
stylesheet language is not CSS, or if another stylesheet language is
developed for HTML, then the WebFonts work would presumably be not
applicable. Right now the syntax and semantics are inextricably tied. So
much so that strictly speaking this standard would have to be updated
when CSS2 comes out, or incorporated into it:
"This specification extends the font mechanisms in CSS1..."
I think that it would be possible to define descriptors and algorithms
with a variable syntax and present a *sample syntax* that happens to be
CSS for pedagogic purposes. This could save a lot of work later on as
well as perhaps extend the specification's applicability -- perhaps even
to non-web applications.