Relaxed SIMD (Single Instruction Multiple Data) introduces local non-determinism, where the results of the instructions may vary based on hardware support.

Anchor position container queries with the @container anchored(fallback: …) at-rule apply styles to an element based on the element's anchor position.

The font-language-override CSS property sets which language-specific glyphs are displayed.

The :target-current CSS pseudo-class selects the active scroll marker (as in ::scroll-marker), while the :target-after and :target-before pseudo-classes select the inactive markers preceding and following the active scroll marker.

The @container style() CSS at-rule and if(style()) CSS function queries accept a range syntax, such as >, <, >=, <=, to query for inexact values.

Interest invokers, registered by the interestfor HTML attribute, trigger events and actions on a target element when a user shows interest in the element, through behaviors such as hover, focus, or long-press. Pseudo-elements apply styles to sources and targets of interest.

The moveBefore() DOM method relocates a node while preserving its state. For example, you can move the active element without losing focus, move an animated element without resetting the animation, or move an iframe without reloading its content.

The screen.orientation.lock() method prevents changes to the screen orientation, typically in fullscreen applications such as games. For example, while locked, rotating a phone to the side won't change the screen orientation from landscape to portrait.

Signature-based resource integrity verifies a script's provenance by checking that the resource has been signed with a trusted key given by the <script> element's integrity attribute.

The digital credentials API issues and requests digital credentials, such as driver's licenses or ID cards, with the browser or operating system. Digital credentials extend the navigator.credentials credential management API.

The anchor() and anchor-size() CSS functions animate or transition on changes such as the anchor box moving or the anchor element changing.

The signalUnknownCredential(), signalAllAcceptedCredentials(), and signalCurrentUserDetails() methods of PublicKeyCredential inform authenticators of the state of public key credentials, so that incorrect or revoked credentials may be updated, removed, or hidden.

The animation-timeline, scroll-timeline, and view-timeline CSS properties advance animations based on the user's scroll position.

The text-wrap: pretty CSS declaration prioritizes better layout over speed when text is broken into multiple lines.

The WebCodecs API provides low-level access to individual video frames and chunks of audio samples, for full control over the way media is processed.

The scroll-target-group CSS property sets the container where anchor links act as scroll markers. Using selectors such as :target-current, you can style elements when a target has scrolled into view. It's an alternative to the ::scroll-marker-group pseudo-element, which generates scroll markers.

The container option of the scrollIntoView() method sets which ancestor scroll container to scroll. The "nearest" value scrolls only the nearest ancestor, instead of the default "all".

The scheduler API provides a way to prioritize all tasks belonging to an application.

The payment extension of a web authentication credential allows a relying party (such as a bank) to create a credential that can be queried by any merchant origin as part of an online checkout that uses the Payment Request API's secure-payment-confirmation payment method. Also known as SPC.

The @function CSS at-rule defines a custom function that takes CSS values or custom properties as arguments, and returns a CSS value. It can be based on conditional logic such as by using the @media at-rule.

The SpeechRecognition API converts audio into text using the device's speech recognition service.

The corner-shape CSS property sets the shape of an element's corners when using border-radius, allowing for shapes other than rounded corners. For example, corner-shape: squircle is a shape in between a square and rounded corner.

The closedby HTML attribute for <dialog> sets which user actions close a dialog. For example, closedby="any" allows the dialog to be closed by clicking outside of it.

The font-variant-emoji CSS property sets the default presentation for emoji characters.

The using and await using declarations and the dispose and asyncDispose symbols manage the lifecycle of resources such as file handles and streams. The DisposableStack and AsyncDisposableStack objects can group, dispose, and coordinate dependencies between multiple disposable resources.

The viewport segment CSS environment variables and media features, and the viewport.segments API, allow you to adapt your layout to devices where the display is split, such as on foldable devices.

The Summarizer API uses an on-device language model to summarize text.

The CookieStore API is an asynchronous and promise-based API for managing cookies. It does not rely on document and so is available to service workers as well.

The if() CSS function is an inline conditional value that returns a value based on a set of conditions.

The reading-flow CSS property sets the order in which flex or grid elements are rendered to speech or reached via focus navigation. The reading-order property overrides this order.