Mozilla Mandates Transparency for Firefox Extension Data Collection

Mozilla has announced mandatory data collection transparency requirements for new Firefox extensions, marking a significant shift in browser add-on oversight and user privacy protection.

Starting November 3rd, 2025, all newly submitted Firefox extensions must declare whether they collect or transmit personal data directly within their manifest.json configuration file.

This transparency requirement represents Mozilla’s effort to enhance user awareness regarding how browser extensions handle sensitive information.

Developers will need to utilize the browser_specific_settings.gecko.data_collection_permissions key to specify their data collection practices, with extensions claiming no data collection required to explicitly declare this status.

User-Facing Transparency Implementation

The disclosed data collection information will appear prominently during the extension installation process, displayed alongside other requested permissions.

Beyond the installation phase, this transparency extends across multiple Mozilla platforms.

Users will encounter this data collection disclosure on the addons.mozilla.org listing pages for publicly available extensions, as well as within Firefox’s built-in about:addons page under the Permissions and Data section.

This multi-layered disclosure approach ensures users encounter this critical information throughout their extension interaction lifecycle.

Developer Compliance Requirements

Mozilla has structured the implementation to balance transparency with developer flexibility.

The new framework applies exclusively to newly submitted extensions, exempting existing extensions from immediate compliance.

However, once a developer implements the data_collection_permissions keys in any version, they must maintain this framework for all subsequent releases.

Extensions failing to comply with these requirements will face submission rejection at the addons.mozilla.org signing stage, accompanied by explanatory messaging from Mozilla.

To accommodate browser version compatibility, developers supporting Firefox versions before 140 for Desktop or 142 for Android must continue providing users with clear data collection controls immediately following installation.

This consideration recognizes the diversity of Firefox versions currently in active use across user populations.

Phased Rollout and Future Development

While currently limited to new extensions, Mozilla plans to expand these requirements comprehensively.

The organization has committed to mandating adoption across all extensions during the first half of 2026, though advance notification will precede this transition.

Mozilla is simultaneously developing additional features designed to streamline the implementation process for developers while improving user comprehension of extension data practices.

This initiative reflects Mozilla’s broader commitment to privacy-centered browser design and user empowerment.

By institutionalizing data collection transparency at the extension level, Mozilla addresses longstanding privacy concerns regarding third-party add-ons’ access to user information.

The phased implementation strategy demonstrates consideration for the established extension ecosystem while establishing clear expectations for future submissions.

The requirement aligns with contemporary privacy advocacy trends and regulatory frameworks emphasizing informed consent.

As browser extensions continue functioning as privileged applications with significant data access capabilities, Mozilla’s transparency mandate represents a pragmatic approach to reconciling extension functionality with user privacy interests.

Developers should begin reviewing their data collection practices and prepare for implementation before the November deadline for new submissions and the upcoming universal requirement in 2026.

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