Adding missing descriptions and making them mandatory/published

feature-group-definitions/array-group.yml

@@ -1,4 +1,5 @@
 name: Array grouping
+description: The `Object.groupBy()` and `Map.groupBy()` static methods group elements of iterables based on a function that returns a key for each element of the iterable.
 spec: https://tc39.es/proposal-array-grouping/
 group: maps
 status:

feature-group-definitions/async-await.yml

@@ -1,4 +1,5 @@
 name: Async functions
+description: The `async` and `await` keywords enable the asynchronous, promise-based behavior of a function to be written without using promise chains.
 spec: https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#sec-async-function-definitions
 caniuse: async-functions
 snapshot: ecmascript-2017

feature-group-definitions/async-clipboard.yml

@@ -1,4 +1,5 @@
 name: Async clipboard
+description: The Clipboard API provides asynchronous read and write access to the content of the system clipboard, by requesting permission from the user.
 spec: https://w3c.github.io/clipboard-apis/#async-clipboard-api
 caniuse: async-clipboard
 status:

feature-group-definitions/avif.yml

@@ -1,4 +1,5 @@
 name: AVIF
+description: The AV1 Image File Format (AVIF) is an image format specification for storing images or image sequences compressed with AV1.
 spec: https://aomediacodec.github.io/av1-avif/
 caniuse: avif
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/3798

feature-group-definitions/backdrop-filter.yml

@@ -1,4 +1,5 @@
 name: backdrop-filter
+description: The `backdrop-filter` CSS property applies graphical effects such as blurring or color shifting to the area behind an element.
 spec: https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty
 caniuse: css-backdrop-filter
 compat_features:

feature-group-definitions/background-fetch.yml

@@ -1,4 +1,5 @@
 name: Background fetch
+description: The Background Fetch API allows service workers to delegate downloading large amounts of data to the system, even when the web page is closed.
 spec: https://wicg.github.io/background-fetch/
 status:
   baseline: false

feature-group-definitions/background-gradients.yml

@@ -1,4 +1,5 @@
 name: Background gradients
+description: The CSS gradient functions create background images consisting of progressive transitions between two or more colors.
 spec: https://drafts.csswg.org/css-images-4/#gradients
 caniuse:
   - css-gradients

feature-group-definitions/bigint.yml

@@ -1,4 +1,5 @@
 name: BigInt
+description: BigInt is a built-in JavaScript type that represents numeric values which are too large to be represented by the Number type.
 spec: https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-bigint-objects
 caniuse: bigint
 snapshot: ecmascript-2020

feature-group-definitions/border-image.yml

@@ -1,4 +1,5 @@
 name: Border images
+description: The `border-image` CSS property draws an image around an element's border.
 spec: https://drafts.csswg.org/css-backgrounds-3/#border-images
 caniuse: border-image
 usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/43

feature-group-definitions/cascade-layers.yml

@@ -1,4 +1,5 @@
 name: Cascade layers
+description: CSS Cascade Layers solve CSS rule specificity conflicts by providing priority levels for different groups of CSS rules, such as low-priority styles like resets, and high-priority styles like UI components.
 spec: https://drafts.csswg.org/css-cascade-5/#layering
 caniuse: css-cascade-layers
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/4007

feature-group-definitions/check-visibility.yml

@@ -1,4 +1,5 @@
 name: checkVisibility()
+description: The `Element.checkVisibility()` method checks if an element is visible.
 spec: https://drafts.csswg.org/cssom-view-1/#dom-element-checkvisibility
 compat_features:
   - api.Element.checkVisibility

feature-group-definitions/class-syntax.yml

@@ -1,4 +1,5 @@
 name: Classes
+description: The `class` JavaScript keyword defines a new class, which is a type of function that can be instantiated multiple times by using the `new` keyword.
 caniuse: es6-class
 spec: https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#sec-class-definitions
 snapshot: ecmascript-2015

feature-group-definitions/colrv1.yml

@@ -1,4 +1,5 @@
 name: COLRv1
+description: The COLRv1 font format is used by color fonts to support multi-color glyphs.
 spec: https://www.iso.org/standard/87621.html
 caniuse: colr-v1
 compat_features:

feature-group-definitions/compression-streams.yml

@@ -1,4 +1,5 @@
 name: Compression streams
+description: The JavaScript Compression Streams API compresses and decompresses streams of data using the gzip or deflate formats.
 spec: https://wicg.github.io/compression/
 usage_stats:
   - https://chromestatus.com/metrics/feature/timeline/popularity/3060 # CompressionStream

feature-group-definitions/constraint-validation.yml

@@ -1,4 +1,5 @@
 name: Constraint validation API
+description: The Constraint Validation API provides a programmatic way to validate form controls.
 spec: https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#the-constraint-validation-api
 caniuse: constraint-validation
 status:

feature-group-definitions/contain-intrinsic-size.yml

@@ -1,4 +1,5 @@
 name: contain-intrinsic-size
+description: The `contain-intrinsic-size` CSS property sets the size of an element that the browser will use for layout calculations when the element is subject to size containment, within a CSS query container.
 spec: https://drafts.csswg.org/css-sizing-4/#intrinsic-size-override
 # Shown as "intrinsic-size" on chromestatus.com, but 651 is contain-intrinsic-size.
 usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/651

feature-group-definitions/container-queries.yml

@@ -1,4 +1,5 @@
 name: Container queries
+description: CSS container queries apply styles to an element based on the size of its container.
 spec: https://drafts.csswg.org/css-contain-3/#container-queries
 caniuse: css-container-queries
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/4165

feature-group-definitions/container-style-queries.yml

@@ -1,4 +1,5 @@
 name: Container style queries
+description: CSS style container queries apply styles to an element based on the computed styles of its container.
 spec: https://drafts.csswg.org/css-contain-3/#style-container
 caniuse: css-container-queries-style
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/4550

feature-group-definitions/content-visibility.yml

@@ -1,4 +1,5 @@
 name: content-visibility
+description: The `content-visibility` CSS property controls whether the browser should skip an element's rendering, including layout and painting, until it is needed.
 spec: https://drafts.csswg.org/css-contain-2/#content-visibility
 caniuse: css-content-visibility
 status:

feature-group-definitions/custom-elements.yml

@@ -1,4 +1,5 @@
 name: Custom elements
+description: Custom elements are HTML elements whose behavior is defined by the web developer.
 spec: https://html.spec.whatwg.org/multipage/custom-elements.html
 caniuse: custom-elementsv1
 status:

feature-group-definitions/custom-properties.yml

@@ -1,4 +1,5 @@
 name: Custom properties
+description: Custom properties (also known as CSS variables) are CSS properties prefixed with `--`, and whose values can be reused throughout CSS rules by using the `var()` function.
 spec: https://drafts.csswg.org/css-variables-1/
 caniuse: css-variables
 status:

feature-group-definitions/default.yml

@@ -1,4 +1,5 @@
 name: ":default"
+description: The `:default` CSS pseudo-class selects form elements that are the default in a group of related elements, such as radio input elements which are initially checked, or option elements which are initially checked.
 spec: https://drafts.csswg.org/selectors-4/#the-default-pseudo
 caniuse: css-default-pseudo
 status:

feature-group-definitions/details-name.yml

@@ -1,4 +1,5 @@
 name: Mutually exclusive <details> elements
+description: Multiple `<details>` elements which use the same `name` attribute are mutually exclusive. When one member of the group is opened, all other members are closed.
 spec: https://html.spec.whatwg.org/multipage/interactive-elements.html#attr-details-name
 compat_features:
   - api.HTMLDetailsElement.name

feature-group-definitions/details.yml

@@ -1,4 +1,5 @@
 name: <details>
+description: The `<details>` element creates a disclosure widget which content is visible only when the widget is toggled open, such as when using a nested `<summary>` element.
 spec: https://html.spec.whatwg.org/multipage/interactive-elements.html#the-details-element
 compat_features:
   - api.HTMLDetailsElement

feature-group-definitions/device-posture.yml

@@ -1,4 +1,5 @@
 name: Device posture
+description: The Device Posture API provides information about the physical posture of a device, such as whether a foldable device is folded or unfolded.
 spec: https://w3c.github.io/device-posture/
 status:
   baseline: false

feature-group-definitions/dialog.yml

@@ -1,4 +1,5 @@
 name: "<dialog>"
+description: The `<dialog>` HTML element represents a modal or non-modal dialog box.
 spec: https://html.spec.whatwg.org/multipage/interactive-elements.html#the-dialog-element
 caniuse: dialog
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/481

feature-group-definitions/document-picture-in-picture.yml

@@ -1,3 +1,4 @@
 name: Document picture-in-picture
+description: The Document Picture-in-Picture API makes it possible to open an always-on-top window that can be populated with arbitrary HTML content.
 spec: https://wicg.github.io/document-picture-in-picture/
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/4397

feature-group-definitions/edit-context.yml

@@ -1,2 +1,3 @@
 name: EditContext
+description: The EditContext API is used to build rich text editors that support advanced text input experiences, such as Input Method Editor (IME) composition, emoji picker, or any other platform-specific editing-related UI surfaces.
 spec: https://w3c.github.io/edit-context/

feature-group-definitions/fetch-priority.yml

@@ -1,4 +1,5 @@
 name: Fetch priority
+description: The optional `priority` parameter of the `fetch()` method, and the `fetchPriority` HTML attribute specifies the priority of the fetch request, relative to other requests of the same type.
 spec:
   - https://fetch.spec.whatwg.org/#request-priority
   - https://html.spec.whatwg.org/multipage/urls-and-fetching.html#fetch-priority-attributes

feature-group-definitions/flexbox-gap.yml

@@ -1,3 +1,4 @@
 name: Flexbox gap
+description: The `gap` CSS property in a flexbox layout specifies the size of the gap between flex items and between flex lines.
 spec: https://drafts.csswg.org/css-align-3/#gaps
 caniuse: flexbox-gap

feature-group-definitions/flexbox.yml

@@ -1,4 +1,5 @@
 name: Flexbox
+description: CSS Flexbox Layout is a one-dimensional layout system, which lays content out in a linear direction, with optional wrapping.
 spec: https://drafts.csswg.org/css-flexbox-1/
 caniuse: flexbox
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/1692

feature-group-definitions/focus-visible.yml

@@ -1,4 +1,5 @@
 name: ":focus-visible"
+description: The `:focus-visible` CSS pseudo-class selects elements that match the `:focus` pseudo-class and are determined by the browser to be focused using the keyboard or a similar input device.
 spec: https://drafts.csswg.org/selectors-4/#the-focus-visible-pseudo
 caniuse: css-focus-visible
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/2388

feature-group-definitions/font-optical-sizing.yml

@@ -1,4 +1,5 @@
 name: font-optical-sizing
+description: The `font-optical-sizing` CSS property sets whether text rendering is optimized for viewing at different sizes.
 spec: https://drafts.csswg.org/css-fonts-4/#font-optical-sizing-def
 usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/647
 compat_features:

feature-group-definitions/font-palette-animation.yml

@@ -1,4 +1,5 @@
 name: font-palette animation
+description: The `palette-mix()` CSS function creates a new `font-palette` value by blending together two `font-palette` values contained in a color font.
 spec: https://drafts.csswg.org/css-fonts-4/#font-palette-prop
 usage_stats: https://chromestatus.com/metrics/css/timeline/animated/709
 compat_features:

feature-group-definitions/font-palette.yml

@@ -1,4 +1,5 @@
 name: font-palette and @font-palette-values
+description: The `font-palette` CSS property specifies one of the many palettes contained in a color font that browser should use for that font.
 spec:
   - https://drafts.csswg.org/css-fonts-4/#font-palette-prop
   - https://drafts.csswg.org/css-fonts-4/#font-palette-values

feature-group-definitions/font-synthesis.yml

@@ -1,4 +1,5 @@
 name: font-synthesis
+description: The `font-synthesis` CSS shorthand property specifies whether or not the browser should synthesize bold, italic, small-caps, and other typefaces when they're missing from the specified font-family.
 spec: https://drafts.csswg.org/css-fonts-4/#font-synthesis-intro
 usage_stats:
   - https://chromestatus.com/metrics/css/timeline/popularity/700 # font-synthesis-weight

feature-group-definitions/font-variant-alternates.yml

@@ -1,4 +1,5 @@
 name: font-variant-alternates
+description: The `font-variant-alternates` CSS property controls the usage of alternate glyphs for characters, as defined in `@font-feature-values` at-rules.
 spec: https://drafts.csswg.org/css-fonts-4/#font-variant-alternates-prop
 caniuse: font-variant-alternates
 usage_stats: https://chromestatus.com/metrics/css/timeline/popularity/738

feature-group-definitions/fonts.yml

@@ -1,4 +1,5 @@
 name: "@font-face"
+description: The `@font-face` CSS at-rule specifies a custom font with which to display text, which can be loaded from either a remote server or a locally-installed font on the device.
 spec: https://drafts.csswg.org/css-fonts-5/
 caniuse: fontface
 status:

feature-group-definitions/fullscreen.yml

@@ -1,4 +1,5 @@
 name: Fullscreen API
+description: The Fullscreen API is used to present a specific element in fullscreen mode.
 spec: https://fullscreen.spec.whatwg.org/
 caniuse: fullscreen
 compat_features:

feature-group-definitions/grid-animation.yml

@@ -1,4 +1,5 @@
 name: Grid animation
+description: Grid animation allows to animate the `grid-template-columns` and `grid-template-rows` CSS properties.
 spec: https://drafts.csswg.org/css-grid-2/#track-sizing
 status:
   baseline: low

feature-group-definitions/grid.yml

@@ -1,4 +1,5 @@
 name: Grid
+description: CSS Grid Layout is a two-dimensional layout system, which lays content out in rows and columns.
 spec: https://drafts.csswg.org/css-grid-3/
 caniuse: css-grid
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/1693

feature-group-definitions/has.yml

@@ -1,4 +1,5 @@
 name: ":has()"
+description: The `:has()` CSS pseudo-class selects an element if any of the selectors passed as parameters would match at least one element.
 spec: https://drafts.csswg.org/selectors-4/#relational
 caniuse: css-has
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/4743

feature-group-definitions/html-media-capture.yml

@@ -1,4 +1,5 @@
 name: HTML media capture
+description: The `capture` HTML attribute for `<input type="file">` elements allows the user to, optionally, capture media using the device's camera, microphone, or other media-capture capabilities.
 spec: https://w3c.github.io/html-media-capture/
 caniuse: html-media-capture
 compat_features:

feature-group-definitions/http11.yml

@@ -1,4 +1,5 @@
 name: HTTP/1.1
+description: HTTP/1.1 is a revision of the HTTP network protocol used by the World Wide Web.
 spec: https://httpwg.org/specs/rfc9112.html
 compat_features:
   - http.headers.Accept

feature-group-definitions/http2.yml

@@ -1,3 +1,4 @@
 name: HTTP/2
+description: The HTTP/2 protocol is a major revision of the HTTP network protocol, providing improved performance and efficiency by using a single TCP connection to send multiple streams of data at once.
 spec: https://httpwg.org/specs/rfc9113.html
 caniuse: http2

feature-group-definitions/http3.yml

@@ -1,3 +1,4 @@
 name: HTTP/3
+description: HTTP/3 is a major revision of the HTTP network protocol, providing improved performance and efficiency by using QUIC as the underlying transport protocol.
 spec: https://httpwg.org/specs/rfc9114.html
 caniuse: http3

feature-group-definitions/idle-detection.yml

@@ -1,4 +1,5 @@
 name: Idle detection
+description: The Idle Detection API is used to notify a webpage of the user's idle, active, and locked state.
 spec: https://wicg.github.io/idle-detection/
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/2834
 status:

feature-group-definitions/image-set.yml

@@ -1,3 +1,4 @@
 name: image-set()
+description: The `image-set()` CSS function defines a set of images for at different resolutions or pixel densities, which the browser can pick from, depending on the device capabilities.
 spec: https://drafts.csswg.org/css-images-4/#image-set-notation
 caniuse: css-image-set

feature-group-definitions/import-maps.yml

@@ -1,4 +1,5 @@
 name: Import maps
+description: The `type="importmap"` attribute for the `<script>` HTML element indicates that the body of the element contains an import map. An import map is a JSON object that controls how the browser should resolve module specifiers when importing JavaScript modules.
 spec: https://html.spec.whatwg.org/multipage/webappapis.html#import-maps
 caniuse: import-maps
 status:

feature-group-definitions/indeterminate.yml

@@ -1,4 +1,5 @@
-name: ":indeterminate()"
+name: ":indeterminate"
+description: The `:indeterminate` CSS pseudo-class selects any form element whose state is indeterminate, such as checkboxes that have been set to an indeterminate state with JavaScript, or radio buttons which are members of a group in which all radio buttons are unchecked.
 spec:
   - https://drafts.csswg.org/selectors-4/#indeterminate
   - https://html.spec.whatwg.org/multipage/semantics-other.html#selector-indeterminate

feature-group-definitions/intersection-observer.yml

@@ -1,4 +1,5 @@
 name: Intersection observer
+description: 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.
 spec: https://w3c.github.io/IntersectionObserver/
 caniuse: intersectionobserver
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/1368

feature-group-definitions/is.yml

@@ -1,4 +1,5 @@
 name: ":is()"
+description: "The `:is()` CSS pseudo-class function takes a selector list as its argument, and selects any element that can be selected by one of the selectors in that list."
 spec: https://drafts.csswg.org/selectors-4/#matches
 caniuse: css-matches-pseudo
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/2322

feature-group-definitions/jpegxl.yml

@@ -1,4 +1,5 @@
 name: JPEG XL
+description: The JPEG XL format is a raster graphics file format that supports both lossy and lossless compression.
 spec: https://www.iso.org/standard/85253.html
 caniuse: jpegxl
 status:

feature-group-definitions/line-clamp.yml

@@ -1,4 +1,5 @@
 name: line-clamp
+description: The `line-clamp` CSS property limits the text in a block container to a certain number of lines.
 spec: https://drafts.csswg.org/css-overflow-3/#line-clamp
 caniuse: css-line-clamp
 compat_features:

feature-group-definitions/media-query-range-syntax.yml

@@ -1,4 +1,5 @@
 name: Media query range syntax
+description: The range syntax of CSS media queries allows to use mathematical comparison operators such as `<`, `>`, `<=`, and `>=` to define a range of values for a media feature.
 caniuse: css-media-range-syntax
 spec: https://drafts.csswg.org/mediaqueries-4/#mq-range-context
 status:

feature-group-definitions/modulepreload.yml

@@ -1,4 +1,5 @@
 name: '<link rel="modulepreload">'
+description: The `rel="modulepreload"` attribute for the `<link>` HTML element indicates that a module script should be fetched, parsed, and compiled preemptively, and stored for later execution.
 spec: https://html.spec.whatwg.org/multipage/links.html#link-type-modulepreload
 caniuse: link-rel-modulepreload
 compat_features:

feature-group-definitions/motion-path.yml

@@ -1,4 +1,5 @@
 name: Motion path
+description: The `offset` shorthand CSS property animates an element along a defined motion path.
 spec: https://drafts.fxtf.org/motion-1/
 caniuse: css-motion-paths
 status:

feature-group-definitions/navigation.yml

@@ -1,2 +1,3 @@
 name: Navigation API
+description: The Navigation API provides mechanisms to initiate, intercept, and manage browser navigation actions.
 spec: https://html.spec.whatwg.org/multipage/nav-history-apis.html#navigation-api

feature-group-definitions/nesting.yml

@@ -1,4 +1,5 @@
 name: Nesting
+description: For shorter selectors, easier reading, and more modularity, CSS rules can be nested inside other rules.
 spec: https://drafts.csswg.org/css-nesting-1/
 caniuse: css-nesting
 status:

feature-group-definitions/offscreen-canvas.yml

@@ -1,4 +1,5 @@
 name: Offscreen canvas
+description: The `OffscreenCanvas` interface provides a canvas that can be drawn to off screen, with no dependencies on the DOM, which can be used to run heavy rendering operations inside a worker context.
 spec: https://html.spec.whatwg.org/multipage/canvas.html#the-offscreencanvas-interface
 caniuse: offscreencanvas
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/1624

feature-group-definitions/overflow-shorthand.yml

@@ -1,4 +1,5 @@
 name: overflow
+description: The `overflow` shorthand CSS property sets the values of the `overflow-x` and `overflow-y` properties.
 spec: https://drafts.csswg.org/css-overflow-3/#propdef-overflow
 caniuse: css-overflow
 status:

feature-group-definitions/picture-in-picture.yml

@@ -1,4 +1,5 @@
 name: Picture-in-picture
+description: The Picture-in-Picture API allow websites to create a floating, always-on-top video window.
 spec: https://w3c.github.io/picture-in-picture/
 caniuse: picture-in-picture
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/2444

feature-group-definitions/popover.yml

@@ -1,4 +1,5 @@
 name: Popover
+description: The Popover API is used to display content on top of other page content, and is controlled either declaratively using HTML attributes, or via JavaScript.
 spec: https://html.spec.whatwg.org/multipage/popover.html
 usage_stats: https://chromestatus.com/metrics/feature/timeline/popularity/4191
 status:

feature-group-definitions/read-write-pseudos.yml

@@ -1,4 +1,5 @@
-name: ":read and :write"
+name: ":read-only and :read-write"
+description: The `:read-only` and `:read-write` CSS pseudo-classes match elements that are read-only or read-write, respectively, such as when `<input>` or `<textarea>` elements have the `readonly` attribute set or not set, respectively.
 spec:
   - https://html.spec.whatwg.org/multipage/semantics-other.html#selector-read-only
   - https://drafts.csswg.org/selectors-4/#rw-pseudos