Firefox Extensions Must Now Disclose User Data Collection
Mozilla has announced new transparency rules for Firefox extension developers, requiring them to clearly disclose what user data their add-ons collect. The policy takes effect on November 3, 2025, and will become mandatory in the first half of 2026.
Developers must declare all data collection
Under the new policy, developers will have to specify the exact types of data gathered by their extensions — such as browsing history, user interactions, or system information — directly in the add-on’s manifest.json file.
This data declaration will appear both during installation and on the addons.mozilla.org listing page, allowing users to see what information is collected before downloading. Mozilla says the goal is to provide full visibility into how extensions interact with personal data.
Timeline and enforcement
The updated requirements will first apply to newly published extensions. Existing add-ons will only need to comply once they are updated after the rule’s effective date.
Any developer who fails to provide accurate data collection details — or intentionally omits them — will face moderation rejection. In other words, extensions that misrepresent privacy practices will not be approved for publication or updates on the Firefox Add-ons platform.
Mozilla’s goal: transparency and user trust
Mozilla emphasized that the new framework aligns with its ongoing mission to promote privacy-first web experiences. The organization noted that while many browser extensions are safe, others have been caught secretly harvesting data or integrating hidden trackers.
By enforcing data declarations at the manifest level, Firefox aims to set a new standard for transparency in the browser ecosystem — similar to privacy labels on mobile app stores like Apple’s App Store and Google Play.
Impact on the developer ecosystem
For developers, the change adds a new layer of documentation and accountability. Mozilla will provide templates and validation tools to simplify compliance, ensuring smaller teams can adapt without major disruption.
Security experts believe this move could help curb “data leakage” incidents, especially among free extensions that rely on hidden analytics or ad networks for revenue. It also reinforces Firefox’s position as one of the few browsers actively prioritizing user privacy over monetization.
Conclusion
With these new rules, Mozilla sets a clear example for transparency in browser extensions. By making data practices visible at the point of installation, Firefox empowers users to make informed choices — a critical step in restoring confidence in the modern web ecosystem.
As the new standards roll out through 2026, the browser landscape may finally move closer to a more ethical and user-centric future.
Editorial Team — CoinBotLab