You can now keep more — or fewer — pinned tabs

Version 140.0, first offered to Release channel users on June 24, 2025

New

• Vertical Tabs: You can now keep more — or fewer — pinned tabs in view for quicker access to important windows. Just drag the divider to resize your pinned tabs section.
• Custom Search Engines: Firefox now supports adding even more search engines. To add a custom engine, right-click a search field of a supported website and select “Add Search Engine”, or go to Settings > Search > Add (below the search shortcuts table) to manually enter a search URL.
• Firefox Extensions: Customize your toolbar with the option to remove the extensions shortcut, giving you more control over your browser. When the button is hidden, you can access the extensions panel again at any time from the Firefox menu by clicking the Extensions menu item.
• You can now unload tabs by right-clicking on a tab (or multiple selected tabs) and selecting "Unload Tab". This can speed up performance by reducing Firefox's memory and CPU usage.
• Full-Page Translations now prioritizes translating only the content near your current view, improving speed and responsiveness. Content outside your view is skipped unless you scroll to it, reducing unnecessary resource usage.
• Firefox builds in Arabic now come with a built-in Arabic dictionary for the Firefox spellchecker.
• Address autofill enabled for users in Italy, Poland, and Austria.

Fixed

• Various security fixes.

Changed

• The Pocket toolbar icon, as well as the Pocket integrations on New Tab, have been removed per the service shutdown announcement.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 140 Release Notes.

Developer

• Improved the search feature in the Inspector panel to help developers more effectively search the DOM of the current page. Sorting the results by the number of matching elements, support “pseudo” selector state, etc.

Web Platform

• Added platform support for aria-keyshortcuts in Linux, macOS, and Windows.
• Added support for the CookieStore API, an asynchronous cookie API for scripts running in HTML documents and service workers.
• Added support for the Custom Highlight API, which allows styling arbitrary text ranges. Support for text-decoration is not included and is planned for an upcoming release.
• Added support for the pointerrawupdate event. This event provides lower-latency access to pointer movements by firing as soon as the pointer data is available, typically before the main pointermove event. Unlike pointermove, it performs an additional hit test to determine the target and fires more frequently, which may impact performance even if only a listener is added. This event is intended for applications that require high-precision input handling and cannot achieve smooth interaction using coalesced pointermove events alone.
• Service Workers are now available in Private Browsing Mode. This enhancement builds on our efforts to support IndexedDB and the DOM Cache API in Private Browsing through encrypted storage. With this change, more websites, especially those that rely on background tasks, will be able to benefit from Service workers.
• Firefox now applies a uniform user agent (UA) style to
• # elements, regardless of whether they are used inside <article>, <aside>, <nav>, or <section>.
• Firefox will now escape less-than () symbols when serializing HTML attributes, making certain mXSS attacks on websites more difficult.