Hi Team, Currently we have following FIXME, which leads to WPT Test failure: FIXME Source: https://github.com/WebKit/WebKit/blob/3604d4d6c245c0eb8a7c5f3fae77acadf31dabe0/Source/WebCore/dom/InlineStyleSheetOwner.cpp#L152 "FIXME: Should MIME types really be case sensitive in XML documet..." WPT Test Case (Live Link): http://wpt.live/html/semantics/document-metadata/the-style-element/style_type_svg.svg ^ We fail third test case: "With a mixed-case type attribute, the style should apply" and Chrome also fail this test case. Only Firefox passes all test cases. Web-Spec: https://html.spec.whatwg.org/multipage/semantics.html#update-a-style-block ___ By modifying return and removing unused 'element' in above function, I get 'PASS' on WPT Test case. inline bool isValidCSSContentType(const AtomString& type) { // https://html.spec.whatwg.org/multipage/semantics.html#update-a-style-block if (type.isEmpty()) return true; return equalLettersIgnoringASCIICase(type, "text/css"_s); } ____ Any input or any concern before I try doing PR? Thanks!