Here’s what’s going on in the world of extensions

Credit: Nick Velazquez / Mozilla

About one-third of Firefox users have installed an add-on before – whether it’s an extension to add powerful and customizable features or a visual theme to personalize the web browsing experience. But if you’re unfamiliar, add-ons are sort of like apps for your browser. They can add all kinds of features to Firefox to make browsing faster, safer or just more fun.

The past year introduced some exciting new changes to the extensions world. The majority of these changes are foundational and take place in the deeply technical back-end of the system, typically out of sight of most Firefox users. However, if you pride yourself on hanging out in popular cybersecurity hubs, reading the latest tech news or developing your own extensions then you might have caught wind of some of these changes yourself.

If you’re not in the loop about the new changes in extensions, let us break it down for you!

Several years ago, Google proposed Manifest V3 (aka a number of intrinsic changes to the Chrome extension framework). Many of these changes would introduce incompatibilities between Firefox and Chromium-based browsers. This means developers would need to support two very different versions of their extensions if they wanted them available for both Firefox and Chromium-based browser users – a heavy burden for most developers that could result in some extensions only being available for one browser.

We believe that Firefox users benefit most when they have access to the broadest selection of useful extensions and features available, thus we’ve always placed long-term bets on cross-browser compatibility and a standards-driven feature for extensions.

With that, we agreed to introduce Manifest V3 support for add-ons, maintaining a high level of compatibility to support cross-browser development. However, there are some critical areas — like security and privacy — where our principles call for a different course of action. In a few targeted areas we decided to depart from Chrome’s implementation and incorporate our own distinctively Mozilla elements. Thus Firefox’s version of Manifest V3 will provide cross-browser extension interoperability, along with uniquely improved privacy and security safeguards, and enhanced compatibility for mobile extensions.

If ads give you the ick, then one distinction we’ve made around ad blockers has been especially crucial to privacy-lovers everywhere.

Content blockers are super important to privacy-minded Firefox users and tend to be the most popular type of browser extension. They not only prevent ick-inducing ads from following you around the internet, but they also make browsing faster and more seamless.

So we weren’t surprised to hear that Chrome users were concerned after learning that several of the internet’s most popular ad blockers, like uBlock Origin, would lose some of their privacy-preserving functionality on Google’s web browser, resulting from the changes Manifest V3 brings to Chrome’s extensions platform – changes that strengthen other facets of security, while unfortunately limiting the capabilities of certain types of privacy extensions.

But rest assured that in spite of these changes to Chrome’s new extensions architecture, Firefox’s implementation of Manifest V3 ensures users can access the most effective privacy tools available like uBlock Origin and other content-blocking and privacy-preserving extensions.

The new extensions button on Firefox gives users control

Adopting Manifest V3 also paved the way for a handy new addition to your Firefox browser toolbar: the extensions button. This gives users the ability to inspect and control which extensions have permission to access specific websites you visit.

The majority of extensions need access to user data on websites in order to work, which allows extensions to offer powerful features and cater to a variety of user needs. Regrettably, this level of site access can be misused and jeopardize user privacy. The extensions button essentially provides users with an opt-in capability and choice that didn’t exist before.

The panel shows the user’s installed and enabled extensions and their current permissions. Users are free to grant ongoing access to a website or to make that decision per visit and can remove, report, and manage extensions and their permissions directly from the toolbar. 

And if you’re not seeing those controls for a beloved extension of yours, it’s most likely because it’s not yet available in its Manifest V3 version. Don’t fret! Changes take time.

We love choice, especially when tied to enhancing user privacy and security – a double-win!

At Mozilla, we’re all about protecting your privacy and security – all while offering add-ons and features that enhance performance and functionality so you can experience the very best of the web. If interested, you can find more information about the extensions button at

And if you’re a longtime Chrome user, don’t sweat it! Exploring a safer and more private alternative doesn’t have to be challenging. We can help you make the switch from Chrome to Firefox as your desktop browser in five simple steps. And don’t worry, you can bring along your bookmarks, saved passwords and even browsing history with you!

Interested in exploring thousands of free add-ons created by independent developers from all over the world? Please visit to explore Firefox-recommended add-ons.

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