[XSLT v1.0](https://www.w3.org/TR/xslt-10/), which all browsers adhere to, was standardized in 1999. In the meantime, XSLT has evolved to v2.0 and v3.0, adding features, and growing apart from the old version frozen into browsers. This lack of advancement, coupled with the rise of JavaScript libraries and frameworks that offer more flexible and powerful DOM manipulation, has led to a significant decline in the use of client-side XSLT. Its role within the web browser has been largely superseded by JavaScript-based technologies, such as JSON and React.
Chromium uses the **libxslt** library to process these transformations, and [libxslt was unmaintained](https://discourse.gnome.org/t/stepping-down-as-libxslt-maintainer/27615) for ~6 months of 2025. Libxslt is a complex, aging C codebase of the type notoriously susceptible to memory safety vulnerabilities like buffer overflows, which can lead to arbitrary code execution. Because client-side XSLT is now a niche, rarely-used feature, these libraries receive far less maintenance and security scrutiny than core JavaScript engines, yet they represent a direct, potent attack surface for processing untrusted web content. Indeed, XSLT is the source of several recent high-profile security exploits that continue to put browser users at risk.
For these reasons, Chromium (along with both other browser engines, Gecko and WebKit) plans to deprecate and remove XSLT from the web platform. The modern web is powered by three major browser engines: [Blink](https://www.chromium.org/blink/) (Chromium), [Gecko](https://firefox-source-docs.mozilla.org/overview/gecko.html) (Firefox), and [WebKit](https://webkit.org/) (Safari). They interpret code to render pages.
For more details, see this [Chrome for Developers article](https://developer.chrome.com/docs/web-platform/deprecating-xslt).
From Chrome 158, XSLT will stop functioning on Stable releases.
Stage: Origin trial
Current viewport heuristics for speculation rules don't give any room for developer experimentation.
This experimental feature will provide such controls, and enable developers to figure out if different heuristics parameters give them better results than the default ones.
This is a feature only aimed at experimentation, and there are no plans to ship it as is.
Stage: Origin trial
Modern browsers can provide capabilities to augment the browsing experience by modifying media in the page on behalf of the user. The advent of generative AI makes it more likely that browsers will add such features.
Sometimes, the replacement content added at the user request might not match other content and functionality in the page, which could confuse the user. Even if this cannot be completely avoided, if authors can observe when replacement happens they can adjust the document to mitigate confusion (e.g., by hiding or adjusting other content).
For example, a user browsing an e-commerce site with a generic product image (e.g., a model wearing a jacket) might wish to imagine themselves wearing the item. The user agent uses generative AI technology to produce that image and present it in place of the model image. The page improves the user experience by removing text referring to the model's dimensions and the garment size depicted, as it may not be correct in the replacement image.
Stage: Origin trial | Specification