rowan.collins wrote:

It turns out this element was being set in
http://en.wikipedia.org/wiki/Template:Vfd_top, which is used in archived VfD
discussions. I'm not sure why it was there, but it was breaking because multiple
archived discussions were being included on one page, thus creating multiple
divs with the same id.

Thinking it would probably do no harm, I removed the offending attribute;
unfortunately, the template was inserted with {{subst:}}, so the changes haven't
had an immediate effect, but future uses of it shouldn't trigger the problem.

Of course, if there *was* a good reason it was there, someone may add it back
in, in which case we may just have to put up with the errors for the sake of
that purpose.