Experimental features in Firefox

This page lists Firefox's experimental and partially implemented features, including those for proposed or cutting-edge web platform standards, along with information on the builds in which they are present, whether or not they are activated "by default", and which preference can be used to activate or deactivate them. This allows you to test the features before they are released.

New features appear first in the Firefox Nightly build, where they are often enabled by default. They later propagate though to Firefox Developer Edition and eventually to the release build. After a feature is enabled by default in a release build, it is no longer considered experimental and should be removed from the topic.

Experimental features can be enabled or disabled using the Firefox Configuration Editor (enter about:config in the Firefox address bar) by modifying the associated preference listed below.

Note: For editors - when adding features to these tables, please try to include a link to the relevant bug or bugs using [Firefox bug <number>](https://bugzil.la/<number>).

HTML

Layout for input type="search"

Layout for input type="search" has been updated. This causes a search field to have a clear icon once someone starts typing in it, to match other browser implementations. (See Firefox bug 558594 for more details.)

Release channel Version added Enabled by default?
Nightly 81 No
Developer Edition 81 No
Beta 81 No
Release 81 No
Preference name layout.forms.input-type-search.enabled

Toggle password display

HTML password input elements (<input type="password">) include an "eye" icon that can be toggled to display or obscure the password text (Firefox bug 502258).

Release channel Version added Enabled by default?
Nightly 96 No
Developer Edition 96 No
Beta 96 No
Release 96 No
Preference name layout.forms.input-type-show-password-button.enabled

Reflecting ARIA attributes

ARIA reflection is enabled for non-IDREF attributes which allows authors to get and set ARIA attributes on DOM elements directly via JavaScript APIs, rather than by using setAttribute and getAttribute, (see Firefox bug 1824980 for more details.)

Release channel Version added Enabled by default?
Nightly 114 Yes
Developer Edition 114 No
Beta 114 No
Release 114 No
Preference name accessibility.ARIAReflection.enabled

CSS

Hex boxes to display stray control characters

This feature renders control characters (Unicode category Cc) other than tab (U+0009), line feed (U+000A), form feed (U+000C), and carriage return (U+000D) as a hexbox when they are not expected. (See Firefox bug 1099557 for more details.)

Release channel Version added Enabled by default?
Nightly 43 Yes
Developer Edition 43 No
Beta 43 No
Release 43 No
Preference name layout.css.control-characters.enabled or layout.css.control-characters.visible

initial-letter property

The initial-letter CSS property is part of the CSS Inline Layout specification and allows you to specify how dropped, raised, and sunken initial letters are displayed. (See Firefox bug 1223880 for more details.)

Release channel Version added Enabled by default?
Nightly 50 No
Developer Edition 50 No
Beta 50 No
Release 50 No
Preference name layout.css.initial-letter.enabled

content-visibility: auto value

The content-visibility CSS property value auto allows content to skip rendering if it is not relevant to the user. (See Firefox bug 1798485 for more details.)

Release channel Version added Enabled by default?
Nightly 113 Yes
Developer Edition 109 No
Beta 109 No
Release 109 No
Preference name layout.css.content-visibility.enabled

Note that the related contentvisibilityautostatechange event and associated ContentVisibilityAutoStateChangeEvent interface were added in version 110, and are gated by the same preference. These can be used by application code to monitor visibility changes and stop processes related to rendering the element when the user agent is skipping its contents. (See Firefox bug 1791759 for more details.)

Single numbers as aspect ratio in media queries

Support for using a single <number> as a <ratio> when specifying the aspect ratio for a media query. (See Firefox bug 1565562 for more details.)

Release channel Version added Enabled by default?
Nightly 70 No
Developer Edition 70 No
Beta 70 No
Release 70 No
Preference name layout.css.aspect-ratio-number.enabled

backdrop-filter property

The backdrop-filter property applies filter effects to the area behind an element. (See Firefox bug 1178765 for more details.)

Release channel Version added Enabled by default?
Nightly 70 No
Developer Edition 70 No
Beta 70 No
Release 70 No
Preference name layout.css.backdrop-filter.enabled

Masonry grid layout

Adds support for a masonry-style layout based on grid layout where one axis has a masonry layout and the other has a normal grid layout. This allows developers to easily create gallery style layouts like on Pinterest. See Firefox bug 1607954 for more details.

Release channel Version added Enabled by default?
Nightly 77 Yes
Developer Edition 77 No
Beta 77 No
Release 77 No
Preference name layout.css.grid-template-masonry-value.enabled

math-style property

The math-style property indicates whether MathML equations should render with normal or compact height. (See Firefox bug 1665975 for more details.)

Release channel Version added Enabled by default?
Nightly 83 No
Developer Edition 83 No
Beta 83 No
Release 83 No
Preference name layout.css.math-style.enabled

fit-content() function

The fit-content() function as it applies to width and other sizing properties. This function is already well-supported for CSS Grid Layout track sizing. (See Firefox bug 1312588 for more details.)

Release channel Version added Enabled by default?
Nightly 91 No
Developer Edition 91 No
Beta 91 No
Release 91 No
Preference name layout.css.fit-content-function.enabled

Scroll-driven animations

Earlier called "scroll-linked animations", a scroll-driven animation depends on the scroll position of a scrollbar instead of time or some other dimension. The scroll-timeline-name and scroll-timeline-axis properties (and the scroll-timeline shorthand property) allow you to specify that a particular scrollbar in a particular named container can be used as the source for a scroll-driven animation. The scroll timeline can then be associated with an animation by setting the animation-timeline property to the name value defined using scroll-timeline-name.

You can alternatively use the scroll() functional notation with animation-timeline to indicate that a scrollbar axis in an ancestor element will be used for the timeline. For more information, see Firefox bug 1676791, Firefox bug 1754897, and Firefox bug 1737918.

Release channel Version added Enabled by default?
Nightly 101 No
Developer Edition 101 No
Beta 101 No
Release 101 No
Preference name layout.css.scroll-linked-animations.enabled

When using the scroll-timeline shorthand property, the order of the property values must be scroll-timeline-name followed by scroll-timeline-axis. The longhand and shorthand properties are now available behind the preference layout.css.scroll-driven-animations.enabled. For more information, see Firefox bug 1807685, Firefox bug 1804573, and Firefox bug 1809005.

Release channel Version added Enabled by default?
Nightly 110 No
Developer Edition 110 No
Beta 110 No
Release 110 No
Preference name layout.css.scroll-driven-animations.enabled

:has() pseudo-class

The :has() pseudo-class selects elements that contain the selectors passed as parameters. (See Firefox bug 1771896 for more details.)

Release channel Version added Enabled by default?
Nightly 103 No
Developer Edition 103 No
Beta 103 No
Release 103 No
Preference name layout.css.has-selector.enabled

@font-face src feature checking

The @font-face src descriptor now supports the tech() function, allowing fallback of whether a font resource is downloaded based on whether the user-agent supports a particular font feature or technology. See Firefox bug 1715546 for more details.

Release channel Version added Enabled by default?
Nightly 105 Yes
Developer Edition 105 No
Beta 105 No
Release 105 No
Preference name layout.css.font-tech.enabled

round() math function

The CSS round() function is a math function that rounds a number (or the result of an expression) based on a selected rounding strategy. See Firefox bug 1764850 for more details.

Release channel Version added Enabled by default?
Nightly 108 Yes
Developer Edition 108 No
Beta 108 No
Release 108 No
Preference name layout.css.round.enabled

font-variant-emoji

The CSS font-variant-emoji property allows you to set a default presentation style for displaying emojis. See (Firefox bug 1461589) for more details.

Release channel Version added Enabled by default?
Nightly 108 Yes
Developer Edition 108 No
Beta 108 No
Release 108 No
Preference name layout.css.font-variant-emoji.enabled

page-orientation

The page-orientation CSS descriptor for the @page at-rule controls the rotation of a printed page. It handles the flow of content across pages when the orientation of a page is changed. This behavior differs from the size descriptor in that a user can define the direction in which to rotate the page. See (Firefox bug 1673987) for more details.

Release channel Version added Enabled by default?
Nightly 111 Yes
Developer Edition 111 No
Beta 111 No
Release 111 No
Preference name layout.css.page-orientation.enabled

prefers-reduced-transparency media feature

The CSS prefers-reduced-transparency media feature lets you detect if a user has enabled the setting to minimize the amount of transparent or translucent layer effects on their device. See (Firefox bug 1736914) for more details.

Release channel Version added Enabled by default?
Nightly 113 No
Developer Edition 113 No
Beta 113 No
Release 113 No
Preference name layout.css.prefers-reduced-transparency.enabled

inverted-colors media feature

The CSS inverted-colors media feature lets you detect if a user agent or the underlying operating system is inverting colors. See (Firefox bug 1794628) for more details.

Release channel Version added Enabled by default?
Nightly 114 No
Developer Edition 114 No
Beta 114 No
Release 114 No
Preference name layout.css.inverted-colors.enabled

SVG

SVGPathSeg APIs

The SVGPathSeg APIs are being unshipped, and have been placed behind a preference. This includes: SVGPathSegList, SVGPathElement.getPathSegAtLength(), SVGAnimatedPathData. (See Firefox bug 1388931 for more details.)

Release channel Version removed Enabled by default?
Nightly 97 No
Developer Edition 97 No
Beta 97 No
Release 97 No
Preference name dom.svg.pathSeg.enabled

JavaScript

Array grouping methods

The Array.prototype.group() and Array.prototype.groupToMap() methods are used to group the elements of an array using a string or value, respectively, returned by a test function. The groupBy method should be used when strings can be used to represent element groups, while groupByToMap() should be used in cases where it makes sense to use a value as the key. (See Firefox bug 1739648 for more details.)

Release channel Version removed Enabled by default?
Nightly 98 Yes
Developer Edition 98 No
Beta 98 No
Release 98 No
Preference name None

String isWellFormed() and toWellFormed() methods

Strings in JavaScript are represented by sequences of unsigned 16-bit integers, and it's possible to have valid string values that are not well-formed Unicode text. The String.prototype.isWellFormed() and String.prototype.toWellFormed() methods are used to check if a string is well-formed Unicode text and to convert a string to well-formed Unicode text, respectively. See tc39/proposal-is-usv-string and Firefox bug 1825005 for more details.

Release channel Version removed Enabled by default?
Nightly 115 No
Developer Edition - -
Beta - -
Release - -
Preference name javascript.options.experimental.well_formed_unicode_strings

APIs

Graphics: Canvas, WebGL, and WebGPU

Hit regions

Whether the mouse coordinates are within a particular area on the canvas is a common problem to solve. The hit region API allows you define an area of your canvas and provides another possibility to expose interactive content on a canvas to accessibility tools.

Release channel Version added Enabled by default?
Nightly 30 No
Developer Edition 30 No
Beta 30 No
Release 30 No
Preference name canvas.hitregions.enabled

WebGL: Draft extensions

When this preference is enabled, any WebGL extensions currently in "draft" status which are being tested are enabled for use. Currently, there are no WebGL extensions being tested by Firefox.

WebGPU API

The WebGPU API provides low-level support for performing computation and graphics rendering using the Graphics Processing Unit (GPU) of the user's device or computer. See Firefox bug 1602129 for our progress on this API.

Release channel Version added Enabled by default?
Nightly 113 Yes
Developer Edition 73 No
Beta 73 No
Release 73 No
Preference name dom.webgpu.enabled

Audio Output API

MediaDevices.selectAudioOutput()

MediaDevices.selectAudioOutput() displays a prompt on desktop systems, from which users can select their desired audio output. See Firefox bug 1699026.

Release channel Version added Enabled by default?
Nightly 111 Yes
Developer Edition 88 No
Beta 88 No
Release 88 No
Preference name media.setsinkid.enabled

WebRTC and media

The following experimental features include those found in the WebRTC API, the Web Audio API, the Media Source Extensions API, the Encrypted Media Extensions API, and the Media Capture and Streams API.

Asynchronous SourceBuffer add and remove

This adds the promise-based methods appendBufferAsync() and removeAsync() for adding and removing media source buffers to the SourceBuffer interface. See Firefox bug 1280613 and Firefox bug 778617 for more information.

Release channel Version added Enabled by default?
Nightly 62 No
Developer Edition 62 No
Beta 62 No
Release 62 No
Preference name media.mediasource.experimental.enabled

AVIF compliance strictness

The image.avif.compliance_strictness preference can be used to control the strictness applied when processing AVIF images. This allows Firefox users to display images that render on some other browsers, even if they are not strictly compliant.

Permitted values are:

  • 0: Accept images with specification violations in both recommendations ("should" language) and requirements ("shall" language), provided they can be safely or unambiguously interpreted.
  • 1 (default): Reject violations of requirements, but allow violations of recommendations.
  • 2: Strict. Reject any violations in requirements or recommendations.
Release channel Version added Default value
Nightly 92 1
Developer Edition 92 1
Beta 92 1
Release 92 1
Preference name image.avif.compliance_strictness

JPEG XL support

Firefox supports JPEG XL images if this feature is enabled. See Firefox bug 1539075 for more details.

Note that, as shown below, the feature is only available on Nightly builds (irrespective of whether the preference is set).

Release channel Version added Enabled by default?
Nightly 90 No
Developer Edition
Beta
Release
Preference name image.jxl.enabled

OpenFont COLRv1 fonts

This feature provides support for the OpenFont COLRv1 font specification. This enables compression-friendly color vector fonts with gradients, compositing and blending to be loaded using the CSS @font-face rule, or the CSS Font Loading API. See Firefox bug 1740530 for more details.

Release channel Version added Enabled by default?
Nightly 105 No
Developer Edition 105 No
Beta 105 No
Release 105 No
Preference name gfx.font_rendering.colr_v1.enabled

Service Workers

Preloading of service worker resources on navigation

The NavigationPreloadManager interface can be used to enable preloading of resources when navigating to a page. Preloading occurs in parallel with worker bootup, reducing the total time from start of navigation until resources are fetched.

Release channel Version added Enabled by default?
Nightly 99 yes
Developer Edition 97 No
Beta 97 No
Release 97 No
Preference name dom.serviceWorkers.navigationPreload.enabled

WebVR API

WebVR API (Disabled)

The deprecated WebVR API is on the path for removal. It is disabled by default on all builds Firefox bug 1750902.

Release channel Version removed Enabled by default?
Nightly 98 No
Developer Edition 98 No
Beta 98 No
Release 98 No
Preference name dom.vr.enabled

HTML DOM API

Popover API

Firefox now supports the Popover API.

The following Web APIs are now implemented:

CSS updates include:

The following HTML global attributes are supported:

See Firefox bug 934425 for more details.

Release channel Version added Enabled by default?
Nightly 114 No
Developer Edition 114 No
Beta 114 No
Release 114 No
Preference name dom.element.popover.enabled

HTMLMediaElement method: setSinkId()

HTMLMediaElement.setSinkId() allows you to set the sink ID of an audio output device on an HTMLMediaElement, thereby changing where the audio is being output. See Firefox bug 934425 for more details.

Release channel Version added Enabled by default?
Nightly 64 No
Developer Edition 64 No
Beta 64 No
Release 64 No
Preference name media.setsinkid.enabled

HTMLMediaElement properties: audioTracks and videoTracks

Enabling this feature adds the HTMLMediaElement.audioTracks and HTMLMediaElement.videoTracks properties to all HTML media elements. However, because Firefox doesn't currently support multiple audio and video tracks, the most common use cases for these properties don't work, so they're both disabled by default. See Firefox bug 1057233 for more details.

Release channel Version added Enabled by default?
Nightly 33 No
Developer Edition 33 No
Beta 33 No
Release 33 No
Preference name media.track.enabled

ClipboardItem

The ClipboardItem interface of the Clipboard API is now supported and Clipboard.write() accepts a sequence of clipboard items instead of the previously implemented dataTransfer object. It is available behind the pref dom.events.asyncClipboard.clipboardItem which was previously dom.events.asyncClipboard.dataTransfer. See Firefox bug 1619947 for more details.

Release channel Version added Enabled by default?
Nightly 87 No
Developer Edition 87 No
Beta 87 No
Release 87 No
Preference name dom.events.asyncClipboard.clipboardItem

ClipboardRead

The Clipboard.read() method of the Clipboard interface is also now available under the dom.events.asyncClipboard.read preference, when previously it was under dom.events.asyncClipboard.clipboardItem. (See Firefox bug 1701512 for more details.)

Release channel Version added Enabled by default?
Nightly 90 No
Developer Edition 90 No
Beta 90 No
Release 90 No
Preference name dom.events.asyncClipboard.read

HTML Sanitizer API

The HTML Sanitizer API allow developers to take untrusted strings of HTML and sanitize them for safe insertion into a document's DOM. Default elements within each configuration property (those to be sanitized) are still under consideration. Due to this the config parameter has not been implemented (see the constructor for more information). See Firefox bug 1673309 for more details.

Release channel Version added Enabled by default?
Nightly 84 No
Developer Edition 84 No
Beta 84 No
Release 84 No
Preference name dom.security.sanitizer.enabled

GeometryUtils methods: convertPointFromNode(), convertRectFromNode(), and convertQuadFromNode()

The GeometryUtils methods convertPointFromNode(), convertRectFromNode(), and convertQuadFromNode() map the given point, rectangle, or quadruple from the Node on which they're called to another node. (See Firefox bug 918189 for more details.)

Release channel Version added Enabled by default?
Nightly 31 Yes
Developer Edition 31 No
Beta 31 No
Release 31 No
Preference name layout.css.convertFromNode.enable

GeometryUtils method: getBoxQuads()

The GeometryUtils method getBoxQuads() returns the CSS boxes for a Node relative to any other node or viewport. (See Firefox bug 917755 for more details.)

Release channel Version added Enabled by default?
Nightly 31 Yes
Developer Edition 31 No
Beta 31 No
Release 31 No
Preference name layout.css.getBoxQuads.enabled

ElementInternals: Form associated custom element methods and properties

New ElementInternals properties and methods that allow custom elements to interact with a form:

  • The form property gets the form associated with the element.
  • The labels property gets the list of labels associated with the element.
  • The willValidate property checks if a custom form element will be validated.
  • The setFormValue() method sets the sanitized value and user-entered data, if needed.

See these bugs for details: Firefox bug 1556362, Firefox bug 1556373, Firefox bug 1556365, Firefox bug 1556449.

Release channel Version added Enabled by default?
Nightly 95 Yes
Developer Edition 95 No
Beta 95 No
Release 95 No
Preference name dom.webcomponents.formAssociatedCustomElement.enabled

Payment Request API

Primary payment handling

The Payment Request API provides support for handling web-based payments within web content or apps. Due to a bug that came up during testing of the user interface, we have decided to postpone shipping this API while discussions over potential changes to the API are held. Work is ongoing. (See Firefox bug 1318984 for more details.)

Release channel Version added Enabled by default?
Nightly 55 No
Developer Edition 55 No
Beta 55 No
Release 55 No
Preference name dom.payments.request.enabled and
dom.payments.request.supportedRegions

WebShare API

The Web Share API allows sharing of files, URLs and other data from a site. This feature is enabled on Android in all builds, but behind a preference on Desktop (unless specified below).

Release channel Version changed Enabled by default?
Nightly 71 No (default). Yes (Windows from version 92)
Developer Edition 71 No
Beta 71 No
Release 71 No (Desktop). Yes (Android).
Preference name dom.webshare.enabled

Screen Orientation API

ScreenOrientation.lock()

The ScreenOrientation.lock() method allows a device to be locked to a particular orientation, if supported by the device and allowed by browser pre-lock requirements. Typically locking the orientation is only allowed on mobile devices when the document is being displayed full screen. See Firefox bug 1697647 for more details.

Release channel Version changed Enabled by default?
Nightly 111 Yes
Developer Edition 97 No
Beta 97 No
Release 97 No.
Preference name dom.screenorientation.allow-lock

Prioritized Task Scheduling API

The Prioritized Task Scheduling API provides a standardized way to prioritize all tasks belonging to an application, whether they defined in a website developer's code, or in third party libraries and frameworks.

This is enabled on Firefox Nightly (only) from Firefox 101. No preference is provided to allow it to be enabled in other releases.

Security and privacy

Block plain text requests from Flash on encrypted pages

In order to help mitigate man-in-the-middle (MitM) attacks caused by Flash content on encrypted pages, a preference has been added to treat OBJECT_SUBREQUESTs as active content. See Firefox bug 1190623 for more details.

Release channel Version added Enabled by default?
Nightly 59 No
Developer Edition 59 No
Beta 59 No
Release 59 No
Preference name security.mixed_content.block_object_subrequest

Insecure page labeling

These two preferences add a "Not secure" text label in the address bar next to the traditional lock icon when a page is loaded insecurely (that is, using HTTP rather than HTTPS). See Firefox bug 1335970 for more details.

Release channel Version added Enabled by default?
Nightly 60 No
Developer Edition 60 No
Beta 60 No
Release 60 No
Preference name security.insecure_connection_text.enabled for normal browsing mode; security.insecure_connection_text.pbmode.enabled for private browsing mode

Upgrading mixed display content

When enabled, this preference causes Firefox to automatically upgrade requests for media content from HTTP to HTTPS on secure pages. The intent is to prevent mixed-content conditions in which some content is loaded securely while other content is insecure. If the upgrade fails (because the media's host doesn't support HTTPS), the media is not loaded. (See Firefox bug 1435733 for more details.)

This also changes the console warning; if the upgrade succeeds, the message indicates that the request was upgraded, instead of showing a warning.

Release channel Version added Enabled by default?
Nightly 84 Yes
Developer Edition 60 No
Beta 60 No
Release 60 No
Preference name security.mixed_content.upgrade_display_content

Permissions Policy / Feature policy

Permissions Policy allows web developers to selectively enable, disable, and modify the behavior of certain features and APIs in the browser. It is similar to CSP but controls features instead of security behavior. Note that this is implemented in Firefox as "Feature Policy, the name used in an earlier version of the specification.

Release channel Version added Enabled by default?
Nightly 65 No
Developer Edition 65 No
Beta 65 No
Release 65 No
Preference name dom.security.featurePolicy.header.enabled

Clear-Site-Data "cache" directive

The Clear-Site-Data HTTP response header cache directive clears the browser cache for the requesting website.

Note: This was originally enabled by default, but put behind a preference in version 94 (Firefox bug 1729291).

Release channel Version added Enabled by default?
Nightly 63 No
Developer Edition 63 No
Beta 63 No
Release 63 No
Preference name privacy.clearsitedata.cache.enabled

HTTP

SameSite=Lax by default

SameSite cookies have a default value of Lax. With this setting, cookies are only sent when a user is navigating to the origin site, not for cross-site subrequests to load images or frames into a third party site and so on. For more details see Firefox bug 1617609.

Release channel Version added Enabled by default?
Nightly 69 No
Developer Edition 69 No
Beta 69 No
Release 69 No
Preference name network.cookie.sameSite.laxByDefault

HTTP Status 103

The 103 Early Hints HTTP information response status code may be sent by a server to allow a user agent to start preloading resources while the server is still preparing the full response. For more details see Firefox bug 1813035.

Release channel Version added Enabled by default?
Nightly 111 Yes
Developer Edition 111 Yes
Beta 111 Yes
Release 102 No
Preference name network.early-hints.enabled and network.early-hints.preconnect.enabled

Access-Control-Allow-Headers wildcard does not cover Authorization

The Access-Control-Allow-Headers is a response header to a CORS preflight request, that indicates which request headers may be included in the final request. The response directive can contain a wildcard (*), which indicates that the final request may include all headers except the Authorization header.

By default, Firefox includes the Authorization header in the final request after recieving a response with Access-Control-Allow-Headers: *. Set the preference to false to ensure Firefox does not include the Authorization header. For more details see Firefox bug 1687364.

Release channel Version added Enabled by default?
Nightly 115 Yes
Developer Edition 115 Yes
Beta 115 Yes
Release 115 Yes
Preference name network.cors_preflight.authorization_covered_by_wildcard

Developer tools

Mozilla's developer tools are constantly evolving. We experiment with new ideas, add new features, and test them on the Nightly and Developer Edition channels before letting them go through to beta and release. The features below are the current crop of experimental developer tool features.

Execution context selector

This feature displays a button on the console's command line that lets you change the context in which the expression you enter will be executed. (See Firefox bug 1605154 and Firefox bug 1605153 for more details.)

Release channel Version added Enabled by default?
Nightly 75 No
Developer Edition 75 No
Beta 75 No
Release 75 No
Preference name devtools.webconsole.input.context

Mobile gesture support in Responsive Design Mode

Mouse gestures are used to simulate mobile gestures like swiping/scrolling, double-tap and pinch-zooming and long-press to select/open the context menu. (See Firefox bug 1621781, Firefox bug 1245183, and Firefox bug 1401304 for more details.)

Release channel Version added Enabled by default?
Nightly 76[1] Yes
Developer Edition 76[1] Yes
Beta 76[1] Yes
Release 76[1] No
Preference name n/a

[1] Support for zooming using the double-tap gesture was added in Firefox 76. The other gestures were added for Firefox 79.

Server-sent events in Network Monitor

The Network Monitor displays information for server-sent events. (See Firefox bug 1405706 for more details.)

Release channel Version added Enabled by default?
Nightly 80 Yes
Developer Edition 80 Yes
Beta 80 No
Release 80 No
Preference name devtools.netmonitor.features.serverSentEvents

CSS browser compatibility tooltips

The CSS Rules View can display browser compatibility tooltips next to any CSS properties that have known issues. For more information see: Examine and edit HTML > Browser Compat Warnings.

Release channel Version added Enabled by default?
Nightly 81 No
Developer Edition 81 No
Beta 81 No
Release 81 No
Preference name devtools.inspector.ruleview.inline-compatibility-warning.enabled

UI

Desktop zooming

This feature lets you enable smooth pinch zooming on desktop computers without requiring layout reflows, just like mobile devices do. (See Firefox bug 1245183 and Firefox bug 1620055 for more details.)

Release channel Version added Enabled by default?
Nightly 42 Yes
Developer Edition 42 No
Beta 42 No
Release 42 No
Preference name apz.allow_zooming and (on Windows) apz.windows.use_direct_manipulation

See also