When I click on a link for an RDF/XML document, such as
<http://www.gnome.org/~shaunm/pulse/web/mod/svn.gnome.org/empathy/trunk?doap=empathy.doap>,
Iceweasel opens a download window which informs me that this is an
RDF/XML document and asks what I should do with it: either save it, or
open it with Iceweasel.

Obviously, this is a little silly.  Either Iceweasel knows how to
display application/rdf+xml, or it does not.  If it does, it should do
so without asking me what to do.  If it does not, it should not suggest
itself as a viewer.