This works in the latest Firefox 18.104.22.168 but not Firefox 3. The trunk did get a fix for bug 316394 but that's in CSS and wouldn't have fixed this I don't think. Putting escaped low surrogates into HTML elements correctly leads to unknown tags (e.g. <scr�ipt> doesn't work).
<a href="http://www.moz�illa.com">shouldn't be mozilla</a>
Bug 316394 covered both CSS escapes and HTML numeric entities.
This has now been posted to a higher profile site (microsoft)
The branch merge for bug 316394 fixes this testcase.
Fixed by backporting bug 316394.
I checked in an HTML test for this. We can use bug 316394 to track the xpcom unit tests needed here.
Verified FIXED using : Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:22.214.171.124) Gecko/2008082909 Firefox/126.96.36.199, which yields http://www.moz�illa.com/.
Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:188.8.131.52) Gecko/2008070205 Firefox/184.108.40.206, however, has http://www.mozilla.com.
Replacing fixed220.127.116.11 keyword with verified18.104.22.168; additionally, since this bug seems scoped to the 1.8 branch, marking its state as VERIFIED FIXED.