AdGuard Browser Extension v5.3: A stronger core, a smoother experience
The new AdGuard Browser Extension v5.3 is out, bringing important improvements to speed and stability. At the heart of this update is the filtering engine — now faster, more reliable, and refined for better compatibility with MV3.
Faster filtering engine startup
The filtering engine, known as TSUrlFilter, powers the extension, blocking unwanted content and keeping pages clean. With this update, the engine starts up twice as fast, so the extension runs smoother, and remains stable even after background restarts.
Native :has support
To block and hide page elements, the engine uses CSS selectors — a fast and reliable way to keep pages clean. Previously, :has selectors were injected by the extension itself using extended CSS. Now, where supported, the engine uses the browser’s built-in :has selector instead. This makes filtering more stable and predictable, while also reducing the load on the system.
Improved HTML filtering
A single filtering method is usually not enough on its own. When ads or other elements try to blend in with page content, HTML filtering comes in handy. It works directly with the page’s structure to detect and remove such elements. This update improves HTML filtering and brings it in line with the latest CoreLibs version, offering more accurate handling of :contains rules.
Restored csp_report blocking
Lastly, about our ongoing work with MV3. After moving to the new architecture, the blocking of csp_report requests stopped working, which could let websites collect additional data on blocked content and user activity. This update restores csp_report blocking in an MV3‑compatible way, bringing back the same level of protection and improving user privacy.
Share your feedback
Have an idea or spotted a bug? Let us know on GitHub or social media — every message helps us make AdGuard even better.
