September 2021 web platform update

Now widely available on the web platform
Widely available

Abortable fetch: If you construct a fetch request with an AbortSignal, you can cancel the request. Learn more.
AbortController and AbortSignal: The AbortController and AbortSignal APIs allow you to cancel an ongoing operation, such as a fetch() request. Learn more.
Intersection observer: The Intersection Observer API asynchronously observes changes in the intersection of a target element with an ancestor element or with a top-level document's viewport. Learn more.

aspect-ratio: The aspect-ratio CSS property controls the width-to-height ratio of elements. For <img> and <video> elements, the width and height attributes used together with height: auto control the aspect ratio while the image/video is loading. Learn more.
Logical properties: CSS logical properties control borders, size, margin, and padding with directions and dimensions relative to the writing mode. For example, in a left to right, top to bottom writing mode, block-end refers to the bottom. Also known as flow relative. Learn more.
Referrer policy: The Referrer-Policy HTTP header and referrerpolicy HTML attributes control whether requests have the Referer header and what information the header contains. Learn more.
Web authentication: The web authentication API allows you to create public key-based credentials and use them for authentication, such as when signing in. Also known as WebAuthn. Learn more.
WebGL2: The WebGL2RenderingContext API is the "webgl2" rendering context for the <canvas> element. It represents a space for drawing two- and three-dimensional graphics and animations. It corresponds to OpenGL ES 3.0. Learn more.