See what landed recently in Firefox Nightly!

Starting with Firefox Nightly 135, the DevTools toolbox colors have been updated to have higher contrast than the regular theme when in High Contrast Mode. Note that this change will only be activated when all of these conditions are met:

• High Contrast Mode is enabled for the system.
• In about:settings, in the Colors popup, Use system colors is checked, and Override the colors specified by the page with your selections above is set to something else than Never.
• In DevTools settings, the selected Theme is Auto.

Starting with Firefox Nightly 134, Firefox can now selectively unblock certain social media embeds in ETP Strict or Private Browsing mode, allowing users to access blocked content without decreasing their overall protection level.

On macOS, some background tasks will be moved to lower power cores resulting in less energy use.

Hardware-accelerated playback of HEVC video content is now supported on macOS.

Hardware video decoding is now enabled for AMD GPUs on Linux.

Starting with Firefox 136, profile management is now available in Nightly builds. Users can now more easily create and switch between different profiles.

Firefox will upgrade page loads to HTTPS and gracefully fall back to HTTP if that does not succeed. This behavior is known as HTTPS-First.

Having any issues with a website on Firefox for Android, yet the site seems to be working as expected on another browser? You can now let us know via the Web Compatibility Reporting Tool. To access it:

• Open the Menu via the three-dot button while on a browser tab
• Tap on “Report broken site”

Provide the form with as much information as possible, and you’ll directly help us detect, target, and fix the most impacted sites to make your browsing experience on Firefox smoother.

Firefox will now prefer PNG when copying images out of Firefox, allowing the preservation of transparency.

Starting with Firefox for Android 131, HLS playlist support was deprecated in Nightly builds. Extended testing showed no adverse impact as newer playback technologies have been widely adopted by websites.

Starting with Firefox Nightly 135, macOS DMG packages now use LZMA for compression, reducing download size and installation time.

Starting with Firefox Nightly 135, third-party tracking cookies are now protected by Total Cookie Protection instead of being blocked by default.

Cookie Banner Handling by default in Private Browsing is now disabled. This was previously enabled only in Nightly and Beta. The feature can be enabled via the cookiebanners.service.mode and cookiebanners.service.mode.privateBrowsing prefs in about:config.

The Developer Tools debugger editor now uses Codemirror 6 which improves performance.

Starting in Firefox 135, Nightly builds now send a referrer from meta refreshes and Refresh headers, improving compatibility with sites such as Twitch.

Starting with Firefox 135, the Temporal proposal, a better version of Date, is now available for experimentation in Nightly builds behind the javascript.options.experimental.temporal preference. For more details, see https://tc39.es/proposal-temporal/docs/.

Added support for the Intl.DurationFormat object, this enables language-sensitive duration formatting.

Starting with Firefox 136, support for the SVG 2 path API is now available in Nightly builds

Starting with Firefox 136, support for the SVG discard element is now available in Nightly builds.

Added support for the CSS :open pseudo-class for styling elements that can be toggled “open” to display more content.

Added support for the :has-slotted pseudo-class, allowing authors to style the contents of a <slot> element when it is not empty or not using the default value.

Firefox now supports by default the text replacement feature in an input field on macOS. Web content can enable/disable this using the HTML autocorrect attribute.
Also, Firefox for Android hints if the software keyboard supports autocorrect. If supported, the software keyboard suggests autocorrection.

Starting with Firefox 136, scroll-driven animations is enabled in Nightly builds.

The value plaintext-only can now be specified for the contenteditable attribute, making the raw text of an element editable but without supporting rich text formatting.

Added support for the CookieStore API, an asynchronous cookie API to scripts running in HTML documents and service workers.

Firefox now sends a referrer rom meta refreshes and Refresh headers.

Firefox now supports sending multiple simultaneous versions of the same source over WebRTC, so called simulcast, with the H264 video codec. H264 is the second video codec after VP8 to be supported for sending simulcast.