Firefox Nightly
Release Notes

Starting with Firefox 127, we're enabling a new anti-tracking feature in Nightly: Bounce Tracking Protection. This protection detects bounce trackers based on redirect behavior and periodically purges their cookies & site data to prevent tracking.

Starting with Firefox for Android 128, the new tab strip feature for tablets is available for testing in Nightly builds! This enhancement makes tab management more intuitive and efficient, providing a smoother browsing experience for devices in that form factor. Please share your feedback on Google Play and/or the Mozilla Connect post to help us improve it further.

Starting with Firefox 128, hovering the mouse over an unfocused tab will now display a visual preview of its contents in Nightly builds.

Added support for multiple languages in the same document spoken in macOS VoiceOver.

Starting with Firefox 129, Firefox Nightly blocks third-party cookie access with Enhanced Tracking Protection's Strict mode and also in Private Browsing.

Starting with Firefox 129, Firefox Nightly will automatically try to use a secure HTTPS connection whenever possible when loading a page. This behavior is known as "HTTPS-First", or "HTTPS Upgrades", and has been the default in Firefox's private browsing mode since Firefox 91. Here is a blog post from when this feature was introduced in Private Browsing.

Starting with Firefox 129, location search is available in the weather widget on the new tab page in Firefox Nightly. Users can select their desired location to view the current weather conditions.

Reader View has an enhanced Text and layout menu with new options for character spacing, word spacing, and text alignment. These changes offer users a more accessible reading experience.

Reader View now has a Theme menu with additional Contrast and Gray options. You can also select your own custom colors for text, background, and links from the Custom tab.

Address Autofill enabled for users in France and Germany.

HTTPS is replacing HTTP as the default protocol in the address bar on non-local sites. In case a site is not available via HTTPS, Firefox will fall back to HTTP.

Starting with Firefox 126, the shape() function on clip-path property is now supported in nightly builds.

Starting with Firefox 126, the shape() function on offset-path property is supported in nightly builds.

Starting with Firefox 126, interpolation between path() function and shape() function is now supported in nightly builds.

Starting with Firefox 127, the relative color syntax is supported in CSS color functions in Nightly builds. This allows to create colors based on other colors.

Starting with Firefox 128, Firefox Nightly now has initial support for the CHIPS (Cookies Having Independent Partitioned State) standard.

Added support for querying the encryption key system config in mediaCapabilities.decodingInfo() API.

Added support for Float16Array typed arrays along with new DataView methods for reading and setting Float16 values, and a Math.f16round() static method that can be used to round numbers to 16 bits. The new type is useful for sharing data with a GPU, in particular for use cases where it makes sense to trade off precision for memory consumption.

Added support for @starting-style. This at-rule allows to define styles that are applied to an element when it is first rendered, enabling transitions on elements that are added to the DOM or that have their display type changed from none to another value.

Added support for the transition-behavior CSS property. This property allows us to create a transition on discrete animated CSS properties.