Interestingly, the #1 problem I'm seeing in a quick glance at mozilla.org through the link checker is that the W3C's HTML 4 Strict DTD is returning HTTP 500... hehehehe
Posted by WeirdAl at April 2, 2004 10:30 AMDunno if this would interest you, but Epiphany has a link checker extension (adds a Tools -> Check Links item) and it also adds Tools -> Validate which checks the document (using OpenSP i think).
http://www.gnome.org/projects/epiphany/images/ext-errorviewer.png
http://www.gnome.org/projects/epiphany/extensions.html