WHATWG HTML.
Value: whatwg-html
WHATWG DOM.
Value: whatwg-dom
WHATWG URL.
Value: whatwg-url
WHATWG Encoding.
Value: whatwg-encoding
W3C CSS Snapshot 2026.
Value: css-snapshot-2026
CSS cascade and inheritance.
Value: css-cascade
CSS selectors.
Value: selectors
CSS values and units.
Value: css-values
CSS color.
Value: css-color
CSS backgrounds and borders.
Value: css-backgrounds
CSS images.
Value: css-images
CSS transforms and compositing.
Value: css-effects
CSS display, box, and inline layout.
Value: css-box-layout
CSS writing modes and ruby.
Value: css-writing-modes
CSS flexible box layout.
Value: css-flexbox
CSS grid layout.
Value: css-grid
CSS multi-column layout.
Value: css-multicol
CSS positioning.
Value: css-position
CSS table layout.
Value: css-tables
CSS generated content, lists, and counters.
Value: css-generated-content
CSS paged media and fragmentation.
Value: css-paged-media
CSS media and container queries.
Value: css-conditional
CSS fonts.
Value: css-fonts
Unicode 17 algorithms and data.
Value: unicode-17
MathML Core.
Value: mathml-core