Rule Restructuring: From Pre-Request Interception to Post-Load Hiding
In August 2026, uBlock Origin—the open-source ad blocker serving over 40 million users—reached a pivotal crossroads across major browsers. Microsoft Edge officially announced the deprecation of legacy extension interfaces, following earlier cleanup actions by Google Chrome. As a result, the vast majority of browsers worldwide can no longer run full-featured ad-blocking extensions. Meanwhile, Mozilla Firefox issued a concurrent statement committing to long-term underlying support for full-featured extension capabilities.
The core issue stems from Google’s push for the Manifest V3 extension specification. Under the legacy Manifest V2 architecture, ad blockers acted as network security guards, inspecting and intercepting every web request before it left the browser. Over 100,000 rules could be evaluated locally in real time, preventing ad data from ever leaving remote servers. This saved user network data while dramatically lowering battery consumption during web browsing.
Under the new Manifest V3 specification, however, the browser takes over the execution of blocking rules, restricting extensions to submitting static rule lists. Extensions can no longer intervene directly in network transmissions before requests are made; instead, they are limited to hiding page elements after ads and tracking scripts have already loaded. Comparative benchmarks by the tech community reveal that while the new Lite version can visually eliminate most advertisements, tracking scripts still transmit data in the background. This highlights the fundamental shift of the new specification: reclaiming web control from user extensions and placing it back into the hands of the browser platform.
Engine Monopoly: Ecosystem Lock-in Under 77% Market Share
What makes this technical change so disruptive is the extreme concentration of the browser market. According to StatCounter data from July 2026, Google Chrome holds a 68.22% market share, Microsoft Edge holds 5.37%, Opera stands at 1.88%, and Samsung Internet at 2.06%. Including Brave and Vivaldi, Chromium-based browsers collectively command 77% of the global market.
Although some privacy-focused Chromium forks attempted to maintain legacy webRequest APIs, their reliance on Google’s upstream codebase makes long-term resistance unsustainable. Once upstream repositories permanently remove pre-request network interception interfaces, maintaining custom implementations imposes prohibitive maintenance costs on fork developers. This demonstrates how tech giants modifying browser engines can decisively reshape web-wide rules with absolute dominance.
Figure: Chromium-based browsers dominate the overwhelming majority of global market share. Source: DEV Community
By contrast, Safari holds 16.47% of the market but has never supported the full version of uBlock Origin. Firefox, holding just 3.34% of the market, remains the sole non-Chromium engine supporting full ad-blocking capabilities. To bolster its privacy defenses further, Firefox recently introduced native network-level ad blocking on iOS. By integrating filter rules directly into the engine tier to eliminate third-party ads during the request phase, Firefox demonstrates an ecosystem philosophy sharply distinct from industry giants.
Solo Developer vs. Tech Giants: A Clash of Power
Behind this technical tug-of-war affecting hundreds of millions of users stands a legendary independent developer. uBlock Origin was launched and continues to be maintained by developer Raymond Hill since 2014 as a purely open-source project without corporate backing or monetization motives. Operating solely on principles of user privacy and efficiency, the extension has attracted over 10 million active users on Firefox thanks to its minimal resource footprint and potent blocking capabilities.
The Electronic Frontier Foundation (EFF) warned against this concentration of platform power as early as 2021. Google controls the world’s most widely used browser engine while simultaneously operating one of the largest digital advertising networks globally. When the authority to set browser extension standards resides with an advertising giant, platform security can easily serve as a convenient pretext for curtailing competition and protecting ad revenue.
Figure: Firefox pledges continued support for full-featured uBlock Origin. Source: PCWorld
Even within a constrained environment, community efforts continue to seek breakthroughs. Raymond Hill clarified in community discussions that through rule optimization and script injection, extensions can still maximize protection within their given boundaries. The Firefox version of uBO retains over 10 million active users, proving that a substantial core user base is willing to incur migration costs to preserve true control over their browsing experience.
The Shadow of Commercial Dependency
Analyzing this technical evolution requires examining both security governance and platform ecosystem dynamics. Google’s official rationale for pushing Manifest V3 centers on enhancing extension security, preventing malicious extensions from stealing user data or tampering with web pages via dynamic script execution. Restricting arbitrary script execution objectively mitigates security risks posed by malicious extensions and reduces browser memory leaks caused by poorly coded plugins.
For Firefox, however, hosting exclusive support for full ad blocking is both a key differentiator and a commercial vulnerability. Mozilla’s primary revenue relies on search engine partnership agreements that set Google as the default search engine. As Firefox positions itself on the front lines against Google’s ad ecosystem, the very financial lifeline sustaining its operations could face commercial friction.
With Firefox holding only 3.34% of global market share, this reflects the intense commercial and traffic pressure minority ecosystems endure against platform unification trends. Should financial partnerships shift, whether open-source browsers can sustain independent engine development and ecosystem investment over the long term will face a stern test.
Reshaping the Ownership of Web Control
The evolution of ad-blocking rules encapsulates the broader shift of control over modern internet infrastructure. What was once an open web platform is gradually morphing into a tightly governed application container, squeezing the boundaries of user autonomy.
From a security governance perspective, tightening extension permissions undeniably reduces data theft risks from malicious plugins. From a user autonomy perspective, however, consolidating web rendering control inevitably erodes the depth of privacy protection. In my view, the regression of ad blocking from a universal web standard to a niche feature of minority browsers illustrates how modern web infrastructure has become deeply entwined with the commercial logic of platform giants. Whether the open-source ecosystem can defend this final stronghold under Chromium’s absolute dominance will directly shape the openness of tomorrow’s web. Given my own perspective and background, this analysis of platform commercial logic is based on public reporting and community discussions; readers are welcome to share additional insights.
Reference Links:
- PCWorld Coverage
- HN Discussion (item?id=49319633)
- Lobsters Community Discussion (s/lfmss9)
- StatCounter Browser Market Share Statistics (July 2026)
- EFF Analysis Report
