Introduction

Manifest V3 (MV3) is the latest extension framework that Google introduced for Chrome, bringing significant changes to how browser extensions work. While Google emphasizes security and performance improvements, many developers and privacy advocates have criticized MV3 for limiting certain extension capabilities, particularly around content blocking. Unlike Google, Mozilla is taking a unique approach to MV3 that maintains user control and privacy.

In this blog, we’ll explore how Mozilla’s implementation of Manifest V3 differs from Google’s, its impact on users, and why it matters.

What is Manifest V3?

Manifest V3 is the newest version of the extension framework used by Chrome, Firefox, Edge, and other Chromium-based browsers. It introduces several key changes:

• Blocking WebRequest API: Chrome is replacing the WebRequest API with Declarative Net Request (DNR), which limits how extensions can modify network requests.

• Background Scripts Removal: Persistent background scripts are replaced with service workers, affecting how extensions function in the background.

• Stricter Permissions Model: Extensions now have limited access to certain API functionalities for security reasons.

How Mozilla’s Approach is Different

Mozilla has opted for a more balanced approach that aligns with security improvements while preserving user freedom. Here’s what sets Mozilla’s MV3 apart:

1. Keeping WebRequest API for Content Blocking

One of the biggest concerns with Google’s MV3 implementation is the removal of the WebRequest API, which affects ad blockers and privacy-focused extensions. Mozilla has chosen to retain WebRequest API for content blocking, ensuring that users can still use powerful privacy tools like uBlock Origin without limitations.

2. Supporting Background Scripts

Unlike Chrome, which fully replaces background scripts with service workers, Mozilla provides more flexibility. Firefox extensions can still use background scripts in some cases, ensuring that extensions relying on persistent background processes continue functioning effectively.

3. Flexible Declarative Net Request (DNR) Implementation

While Firefox adopts DNR, Mozilla’s version offers developers more flexibility. They allow higher rule limits for content filtering extensions, ensuring that ad blockers and privacy tools remain effective.

4. Prioritizing User Privacy and Security

Mozilla is implementing MV3 in a way that keeps privacy at the core. While MV3 in Chrome has been criticized for potentially benefiting advertisers by limiting ad blockers, Mozilla’s approach ensures that user privacy is protected, and extensions can still provide robust content filtering.

5. Developer-Friendly Transition

Mozilla has been working closely with the developer community to ensure a smoother transition to MV3. Unlike Chrome, which enforces strict limitations, Firefox is allowing more time for extension developers to migrate without breaking functionality.

Why This Matters for Users

Mozilla’s approach to MV3 directly benefits Firefox users in several ways:

• More Effective Ad Blockers: Firefox users will continue to enjoy powerful ad blockers that aren’t restricted by MV3’s limitations.

• Better Privacy Protection: Mozilla’s stance ensures that extensions can still offer strong privacy protections without interference.

• Less Breakage for Extensions: The transition to MV3 in Firefox is designed to minimize disruption, meaning fewer broken extensions.

Conclusion

While Google’s Manifest V3 changes have sparked controversy due to their restrictive nature, Mozilla has taken a more balanced and user-centric approach. By keeping key extension capabilities intact, Firefox ensures that users continue to enjoy robust privacy protections and a free, open web experience.

As extension users and developers navigate the transition to MV3, Mozilla’s commitment to openness and flexibility makes Firefox a compelling choice for those who prioritize control and privacy over their browsing experience.

What are your thoughts on Mozilla’s approach to Manifest V3? Let us know in the comments!