Ad blocking is alive and well, despite Chrome’s attempts to make it harder

February 6, 2026 TH Author

Chrome’s latest revision of its browser extension architecture, known as Manifest v3 (MV3), was widely expected to make content blocking and privacy extensions less effective than its predecessor, Manifest v2 (MV2).

But when researchers affiliated with Goethe University Frankfurt compared the old and new tools, they could not find much difference.

According to a study titled, “Privacy vs. Profit: The Impact of Google’s Manifest Version 3 (MV3) Update on Ad Blocker Effectiveness,” just published in the peer reviewed publication Proceedings on Privacy Enhancing Technologies (PoPETs), the performance of Chrome’s MV3 architecture is more or less on par with the legacy MV2 specification.

“Our results reveal no statistically significant reduction in ad-blocking or anti-tracking effectiveness for MV3 ad blockers compared to their MV2 counterparts, and in some cases, MV3 instances even exhibit slight improvements in blocking trackers,” conclude authors Karlo Lukic and Lazaros Papadopoulos.

Google announced MV3 back in 2019 when it had become apparent that the powerful capabilities exposed to extension developers through MV2 could be (and were) easily abused. The company’s answer involved a revised set of APIs that limited those capabilities and revised the underlying architecture to improve performance.

The most widely noted of those APIs was the blocking (synchronous) version of chrome.webRequest. Under MV2, it could intercept and modify incoming network data, making it ideal for stopping ads, tracking scripts, and making other interventions.

MV3 stopped supporting the blocking version of chrome.webRequest and replaced it with chrome.declarativeNetRequest. The new API is asynchronous (capable of concurrent task processing) rather than synchronous (processes tasks in sequence), which has performance benefits but is less flexible in terms of adapting to page content on the fly.

This and several other API changes alarmed the makers of content blocking and privacy extensions. Google insisted the changes were necessary for performance, security, and privacy, assurances that seemed disingenuous when considered alongside warnings of the potential revenue impact of ad blocking software in Google’s financial boilerplate.

Despite years of developer grumbling and requests for improvements, the phaseout of MV2 went ahead last year. And not much has changed with respect to the role of Chrome extensions in ad blocking and privacy.

The research by Lukic and Papadopoulos, independently funded and unaffiliated with Google or vendors of privacy tools, found not only that MV3 and MV2 ad blocking and anti-tracking extensions are equally effective, but that MV3 improved anti-tracking by blocking 1.8 more tracking scripts per website on average than the MV2 extensions.

Lazaros Papadopoulos, research assistant at Goethe University, told The Register in an email that the study used the default filter sets for the respective ad blocking extensions in order to mimic the behavior of the typical user and to ensure rule consistency.

Papadopoulos suggests that there’s no longer a reason to choose a browser based on its availability to run legacy MV2 extensions (e.g. Firefox).

“There could be minor cosmetic reasons we describe in the paper, but nothing that from our point of view significantly impacts privacy negatively,” he said. “It is important though to note our study is a snapshot in time, and future changes to MV3 might have an impact.”

The study did not consider how MV3 and MV2 browser extensions compare in terms of performance (e.g., page load speed). And the paper notes that the authors did not test whether MV3’s limit on the number of declarative rules could make MV3 extensions less effective for less frequently visited websites.

That said, developers of Chrome-based extensions have a broader set of concerns than the APIs used for blocking content and tracking scripts. The technical and functional improvements sought by developers have been slow to materialize and the oversight of the Chrome Web Store has been underwhelming – security is still a problem, among other issues.

Still, there’s progress, with features like publisher pages, verified uploads, and changes to the Affiliate Ads Policy that disallow the alteration of affiliate links to steal affiliate revenue. ®