Firefox 120 Enhances Privacy by Default

Mozilla launched Firefox 120 with a set of privacy improvements that become the default behavior for all users, without the need for manual configuration. The update continues the browser's trajectory of differentiating itself through data protection in a market dominated by browsers that monetize user activity for advertising purposes.

What Changes by Default

The most impactful change is the default activation of Total Cookie Protection for all sites — previously available only in private browsing mode or through explicit configuration in advanced preferences. With this feature active, each site receives an isolated cookie "jar": a cookie set by tracking.example.com cannot be read by ad.example.com, eliminating the most common cross-site tracking mechanism.

Firefox 120 also now blocks by default tracking pixels in emails when the user opens links received in Gmail, Outlook, and other webmails — a protection Apple implemented in Mail for iOS but that was not previously available in browsers. Firefox's own internal telemetry was further reduced, with the removal of seven categories of events that collected usage data for specific features.

Performance and Compatibility

Version 120 also brings performance improvements to the Gecko rendering engine, with an 18% reduction in layout time for pages with many text elements, and support for CSS Anchor Positioning and View Transitions — two recent specifications that allow transition animations and more expressive relative positioning without JavaScript. Compatibility with existing extensions was fully maintained, and the new JIT compiler for WebAssembly improves the performance of complex web applications by up to 25% in standard benchmarks.