Chrome's Manifest V3: Why Privacy Extensions Are Getting Weaker

If you've noticed your ad blocker acting strangely in Chrome lately, you're not alone. Google has completed its transition to Manifest V3, a new framework for browser extensions that fundamentally limits what privacy tools can do. The result? Millions of users are now less protected than they were before.

What Is Manifest V3?

Manifest V3 (MV3) is Google's new rulebook for Chrome extensions. Every browser extension must follow a "manifest" that defines what it can and cannot do. The previous version, Manifest V2, gave extensions powerful capabilities to intercept, analyze, and block web requests in real time.

Under MV3, these capabilities are severely restricted. Extensions must now use the Declarative Net Request API, which limits them to predefined rules rather than dynamic, real time filtering. The numbers tell the story: extensions are now capped at 30,000 static rules and just 5,000 dynamic rules.

For context, Ghostery's tracker blocklist alone contains over 4,000 entries, consuming 80% of the dynamic rule allowance immediately. That leaves almost nothing for additional privacy features.

The Real Casualty: uBlock Origin

The most visible victim of this change is uBlock Origin, widely considered the gold standard of ad blocking. Its creator, Raymond Hill, refused to compromise the extension's core principles to fit within MV3's constraints. The result was inevitable: uBlock Origin was removed from the Chrome Web Store entirely.

Chrome users are now offered uBlock Origin Lite, a stripped down version that uses MV3's limited API. While it can block basic ads, it cannot perform the advanced, dynamic filtering that made the original so effective. Sophisticated trackers and ad circumvention techniques slip right through.

The user impact has been significant. Adblock Plus saw its user base drop from 44 million to 37 million during the transition period, a loss of 7 million users in just a few months.

Google's Justification Falls Apart

Google claims MV3 improves "performance, security, and privacy." But privacy researchers have identified a critical flaw in this reasoning.

The stated security concern is that malicious extensions could abuse web request access to steal credentials. But here's the problem: MV3 removes only the ability to block requests. Extensions can still observe all web traffic.

As Ghostery's analysis notes, "The removal of webRequest blocking does not improve the privacy of extensions." Malicious extensions can still watch everything you do online. They just cannot block anything anymore.

This means the change paradoxically reduces security for legitimate users while leaving the actual vulnerability unaddressed. Privacy focused extensions lose their power; malicious ones keep their surveillance capabilities.

Where Privacy Still Works

Not all browsers have followed Google's lead. Firefox explicitly supports both MV2 and MV3, maintaining full functionality for privacy extensions. Mozilla has confirmed it has no plans to remove MV2 support.

Brave takes a different approach entirely. Its built in Shields are patched directly into the browser code, bypassing extension APIs altogether. Brave has committed to continuing support for powerful MV2 extensions including uBlock Origin.

Microsoft Edge has also chosen to support MV2 extensions even after Google's cutoff.

The Bigger Picture: Platform Control vs. User Privacy

The Manifest V3 saga illustrates a broader pattern in technology: platforms making decisions that weaken user privacy tools while claiming the opposite. When a company controls the platform, it controls what protections are available.

Email users face the same dynamic. Gmail's ecosystem determines what privacy protections you can access within it. You cannot install an extension that Google has not approved under its terms.

This is why platform independent privacy tools matter. Gblock works within Gmail's interface but does not depend on browser extension APIs that can be restricted on a whim. Your protection against spy pixels and email tracking remains consistent regardless of what Chrome's next manifest version decides to break.

What You Can Do

If browser privacy matters to you, consider your options:

• Switch browsers. Firefox and Brave offer full support for powerful privacy extensions. Your ad blocker will work as intended.
• Layer your protection. Do not rely on a single tool. Use privacy focused DNS, email protection like Gblock, and browser level blocking together.
• Stay informed. Platform changes can undermine your privacy overnight. Following privacy news helps you adapt before you are caught unprotected.

The Manifest V3 transition is a reminder that privacy is not guaranteed. It must be actively protected, sometimes against the very platforms you use every day. Choose tools and services that put your privacy first, not their advertising revenue.

Protect your inbox. Take control of your data, Gblock has you covered!