the default index page is not valid HTML and does not have a valid doctype. Mozilla uses the doctype to figure out how to render the page, so this really should be correct.
Created attachment 26373 [details] Fixed version that almost validates at http://validator.w3.org/
We (Red Hat) should try to fix this for the next release.
Switching to Beta Team
AFAIK, the one in 7.2 is pretty much valid HTML. It passed the validator with only a couple minor quibbles the time I checked it.