When I used WI to view the DOM of the http://www.w3.org/TR/xmlschema-1/ , I find multiple/duplicate instances of <a name> anshors in the DOM that are not in the source; screenshot here: http://www.w3.org/2008/05/dup-a-name.png The source actually has only one <a id="coss-identity-constraint" name="coss-identity-constraint"/> instance in it. I recognize that this may relate in part to the fact that the page is an XHTML/XML page that uses XML empty-tag syntax, but is being served as text/html. (I also recognize that this may be an HTML DOM issue and not a WI issue, but filing it as a WI issue for now because that's where I as an end user am seeing the actual problem manifested.)
This looks to be a bug in the page itself. As you say, it is being served as text/html, and so is being interpreted as HTML. WebKit doesn't honor self-closing tags in HTML content, so the <a> stays open and is cloned across the </h4>. If you reload the page with the Inspector open, you will see lots of errors added to the Inspector's Console about this issue. Validator.nu also reports this problem. I'm going to mark this bug INVALID since WebKit seems to be doing its job correctly. Please reopen if you think WebKit is at fault here.