Firefox 120 Release: Main Features and Updates

The Firefox 120 web browser has been officially released, along with an update to the long-term support branch (version 115.5.0). Firefox 121 has entered beta testing, with its release scheduled for December 19.

Key New Features in Firefox 120

• Copy Link Without Site Tracking: A new context menu option lets you copy a link’s URL to the clipboard after removing tracking parameters used for cross-site tracking (such as mc_eid and fbclid from Facebook links). For users in Germany, tracking parameters are also stripped when opening links in private browsing or strict Enhanced Tracking Protection (ETP) mode. Other users can enable this via the privacy.query_stripping.enabled setting in about:config. A blacklist of known tracking parameters is used.
• Global Privacy Control (GPC): A new option in the Privacy & Security settings enables GPC, which replaces the “Do Not Track” (DNT) header. GPC informs websites not to sell or use your personal data for tracking.
• Enhanced Canvas API Protection: In strict ETP and private browsing modes, protection against passive user identification via the Canvas API has been improved.
• Automatic Cookie Banner Blocking (Germany): For users in Germany, Firefox now automatically closes cookie consent pop-ups in compliance with EU GDPR requirements. This feature can be enabled in Privacy & Security settings or via the cookiebanners.service.mode parameter in about:config (0 = off, 1 = always reject, 2 = reject when possible, otherwise accept). Unlike similar features in Brave or ad blockers, Firefox automates user actions rather than hiding the banners. Two modes are available: simulating a mouse click (cookiebanners.bannerClicking.enabled) and injecting a cookie with the selected mode flag (cookiebanners.cookieInjector.enabled).
• TLS Certificate Import: On Windows, macOS, and Android, importing TLS certificates from the OS root store is now enabled by default. This can be disabled in Preferences → Privacy & Security → Certificates.
• Keyboard Shortcuts in about:logins: New shortcuts for editing (Alt + Enter) and deleting (Alt + Backspace) selected accounts.
• Chromium Data Import in Ubuntu Snap: Firefox Snap builds for Ubuntu now support importing data from Chromium also installed as a Snap package.
• Picture-in-Picture Window Snapping: On Linux and Windows, you can now snap the picture-in-picture video window to screen corners by holding Ctrl while moving it.
• Rust-Based Contextual Hints: Integration has begun for a new, portable component for contextual hints in the address bar, rewritten in Rust.
• User Activation API: The new navigator.userActivation API allows detection of whether a user has interacted with a page (e.g., mouse clicks), is currently interacting, or has not interacted at all.
• HTTP 103 “Early Hints” Support: Firefox now supports the HTTP 103 response code, which allows servers to send preliminary headers (such as links to CSS or JavaScript) before the main content, speeding up resource loading.
• New CSS Units and Functions: Added lh and rlh units for line height, and the light-dark() function for specifying colors for both light and dark themes without using prefers-color-scheme media queries.
• JavaScript Date Parsing: Date.parse() now supports additional date formats, such as “01-12-1999”, “1999-1-5”, “10000-01-12”, “99-01-05”, and “1999-01-05 10:00:00”.
• Media Attribute in <source> Elements: The media attribute is now supported in <source> elements within <picture>, <audio>, and <video> tags.
• WasmGC Extension: WebAssembly GC (WasmGC) support is now enabled by default, making it easier to port programs written in garbage-collected languages (like Kotlin and Dart) to WebAssembly.
• Web Developer Tools:
  • Simulate offline mode for tabs.
  • Added a “Pretty Print” button in the style editor for formatting minified CSS (previously, this was automatic).
  • Debugger performance improved by up to 70% with large source files, and breakpoints tied to the “unload” event now work more reliably.
• Android Version: Fixed a bug that caused tabs to close when selected. Work continues on building an open ecosystem for browser add-ons on mobile. By the official launch in December, over 200 add-ons will be available for Firefox for Android on addons.mozilla.org (AMO).

Security Fixes

Firefox 120 addresses 19 vulnerabilities. Fourteen of these (11 grouped under CVE-2023-6212 and CVE-2023-6213) are rated as critical and involve memory management issues such as buffer overflows and use-after-free errors, which could allow attackers to execute code via specially crafted web pages. Another critical vulnerability (CVE-2023-6206) allows clickjacking to confirm permission requests.

Firefox 121 Beta Highlights

• Option to force underline links regardless of CSS settings (helpful for users with color perception issues).
• On Linux, Wayland is now used by default instead of XWayland, improving touchpad, touchscreen gesture support, and per-monitor DPI in Wayland-based environments. Wayland also boosts graphics performance, though there are still issues with bringing picture-in-picture windows to the foreground due to protocol limitations.