Jen Simmons introduces 58 new features and 525 fixes: customizable <select> elements, scroll anchoring, transform-aware anchor positioning, WebAssembly JSPI, CSS :heading pseudo-class, the revert-rule keyword, stretch sizing, top-level await in modules, and immersive <model> environments on visionOS.
webkit.org/blog/17967/news-from-wwdc26-webkit-in-safari-27-beta