> maybe this is "nasty", but it works (I've tested
it) and I would
> prefer it over broken old extensions.
I think it's nasty, but I'd be willing to go for it. Mental? Do you
have any thoughts on this?
as an alternative, we could do the same like with SVG files. There is a
"promote_to_svg_namespace" function in xml/repr-io.cpp, so SVG files
work fine with and without xmlns attribute.