The :has-slotted CSS pseudo-class matches <slot> elements where the fallback content is not shown. The pseudo-class matches any slotted content, including white space, text nodes, or elements.

The protected audience API facilitates advertisement sales by allowing sites to register users as part of an interest group or to choose which ads appear based on those interest groups, while minimizing the ability of advertisers to track specific members of the interest group. Also known as FLEDGE.

The attribution reporting API measures when an ad click or view leads to a conversion, such as a purchase on an advertiser site.

Container scroll-state queries with the @container scroll-state(...) at-rule apply styles to an element based on the sticky positioning, snapped, and scrollable state of the container.

Instructions accept 64-bit memory indexes.

The scroll-initial-target: nearest CSS declaration sets the initial scroll position of its scroll container to the top of the element, much like scrolling to a URL fragment.

The text-box CSS property sets the spacing above and below text based on a font's typographic features. For example, text-box: trim-both ex alphabetic trims the top to the top of the letter x and the bottom to the bottom of most letters, without descenders.

The device posture API and the device-posture CSS media feature reflect the physical posture of a device, such as whether a foldable device is folded or unfolded.

The restrictTo() method on screen capture media tracks limits capture to a specific element, excluding content which might occlude the element itself, such as video conferencing controls.

The showOpenFilePicker(), showDirectoryPicker(), and showSaveFilePicker() methods request access to files and directories on the user's device and returns a handle for reading and writing to them.

The WebAssembly builtin string functions mirror a subset of the JavaScript String API and adapt it to be efficiently callable without JavaScript glue code.

The <input type="week"> HTML element shows a week picker.

The @view-transition CSS rule sets whether a document opts-in to transitions between documents in a multi-page application. Both the old and new document must opt-in for a transition to be triggered.

The blocking="render" attribute for <link>, <script>, and <style> elements blocks rendering until the external script or stylesheet has been loaded. For <link rel="expect">, rendering is blocked until a specific element is in the DOM.

The ruby-overhang CSS property sets whether ruby annotations may overlap adjacent text.

An XRHand object, from the hand attribute of an XRInputSource object, represents a WebXR session's fully-articulated hand tracking model.

Compression Dictionary Transport is a mechanism for using designated HTTP responses as an external dictionary for future HTTP responses for compression schemes that support using external dictionaries (e.g., Brotli and Zstandard)

The box-decoration-break CSS property sets whether box decorations, such as borders or backgrounds, of an element divided across a page, column, or region wraps each fragment or splits across the break.

The justify-self CSS property aligns an item along a container's inline axis in block layouts, like it does in grid layouts. Likewise, the justify-items property sets a default justify-self value for all items in a container in a block layout.

The scrollsnapchanging and scrollsnapchange events fire when a scroll gesture changes the selected scroll snap target.

The CreateVirtualPressureSource WebDriver command creates artificial sources of compute pressure for testing without the need real device sources of compute pressure.

The calc-size() CSS function computes mathematical expressions that include height and width keyword values, for example calc-size(fit-content, size / 2). Not to be confused with the calc() CSS function, which cannot use keyword values.

The interpolate-size CSS property sets whether animations and transitions interpolate between a numeric value and a keyword value, such as from a fixed length to auto or fit-content.

The MediaStreamTrackProcessor and MediaStreamTrackGenerator APIs modify the contents of a media track for merging streams, applying real-time effects like funny hats, and content overlays.

You can animate elements between display: none and any other display value or animate between content-visibility: hidden and any other content-visibility value. This also applies to transitions.

The writingsuggestions HTML attribute turns on or off a browser's writing suggestions. Writing suggestions vary by browser. For example, if turned on then a browser might show inline text completions accepted by pressing Tab.

The <fencedframe> element embeds another HTML page into the current page in a more secure and privacy-preserving way than <iframe> elements.

The navigator.share() method invokes the device's native sharing mechanism and passes text, links, files, and other content to share targets. Also known as the Web Share API.

WebDriver BiDi is a bidirectional protocol that allows a WebDriver client and a browser to communicate with each other.

The notRestoredReasons property of a PerformanceNavigationTiming object explains why the current document was blocked from using the back/forward cache (also known as the bfcache) on navigation.