I think too that Mozilla should contain the real W3C validator of W3C. I personally think without modification. (unlike bug 114188) It gives a lot of advantages as web developer: - you can see if you generates real HTML pages. - you can correct them and explain why it is wrong without any help. - you can use it to point to other people why their pages are wrong. - if it is included inside mozilla, you can even do it for intranet site. - you can detect easily very buggy page with unclosed tags and so on.
This sounds like a horrible bloat. Mozilla as such isn't a development tool. Furthermore: A developer would likely have access to the real thing at all times, so why slow mozilla down with an additional copy. Also note that the product and component for bug 114188 is "Mozilla.org" and "Miscallenous" - not anything to do with the browser product. Recommend WONTFIX!
What about having a sidebar tab that, when open (and only then), automatically calls the w3c validator and displays the result in the sidebar tab? This way there would be no bloat and the validation would only happen when requested by opening the tab.
Duping. I think the various bugs mentioned here cover all the ground this could. *** This bug has been marked as a duplicate of 73105 ***