WebKit had a number of minor parsing bugs that Acid 3 targeted. [...] We have updated our parser to be much closer to the HTML5-specified parsing rules.

Moi qui croyait que le but d'Acid3 était de vérifier l'implémentation des standards.

WebKit has also never parsed DOCTYPEs before. I re-wrote WebKit’s DOCTYPE parsing to match the HTML5 specification, and so now if you put a DOCTYPE into your page it will be present in the DOM. In addition many bugs centered around proper mode resolution (quirks vs. strict) have now been fixed. You can document.write a DOCTYPE for example in a new document and have the correct mode be selected.

Just to illustrate how far browsers are (were) implementing previous specifications of html.