$ show w3c/html-aria
The w3c/html-aria repository maintains the ARIA in HTML W3C specification — a normative document defining which ARIA roles, states, and properties are permitted on each HTML element, plus the implicit ARIA semantics of native HTML. It is not a conventional application; it is a standards artifact with engineered supporting infrastructure: a ReSpec-based spec source (`index.html`) auto-published to gh-pages via GitHub Actions, a corpus of standalone HTML conformance test pages in `tests/`, and a cross-tool implementation report in `results/implementation-results.html`. The repo functions as the authoritative rulebook that accessibility conformance checkers (Nu HTML Validator, axe-core, IBM Equal Access, ARC Toolkit) implement against, so its 'production output' is normative rules consumed by validator software. The test corpus encodes each normative rule as a discrete, self-contained HTML page with explicit pass/fail expectations — for example, pages verifying that `aria-hidden="true"` is forbidden on focusable elements, that `aria-rowspan` must not coexist with a native `rowspan`, and which roles are allowed on `button`, `summary`, `img`, and `li`. The implementation report tracks, per rule and per vendor tool, whether the rule is implemented (yes/partial/missing), linking to tool-specific GitHub issues. The contribution workflow enforces cross-repo coordination: normative changes require a corresponding web-platform-tests PR and coordination with checker maintainers before merging, which is an unusually well-governed process for a spec repository. Maintenance is steady: commits continue through late 2026, the implementation report was updated in March 2026, Dependabot monitors GitHub Actions, and the W3C auto-publish pipeline runs on every push. Technical drift is low — the spec deliberately tracks the WHATWG HTML Living Standard, deprecates (rather than abandons) outdated ARIA features, and is built on the actively maintained ReSpec toolchain. The main fragility is external: implementation gaps in vendor checkers are documented openly in the report, and cross-repo synchronization with WPT and checker projects creates coordination risk, but the repo itself is current and professionally curated.
The LLM identified 3 files worth highlighting for reuse:
A standalone HTML fixture that encodes the normative rule that `aria-hidden="true"` is prohibited on keyboard-focusable elements. The page includes both valid and invalid element instances plus explicit prose stating what a conformance checker must flag. It is fully self-contained (zero imports, no build step), making it directly extractable into any new ARIA-conformance-checker project as a regression fixture — the pattern of translating a prose MUST NOT statement into a discrete machine-evaluable test page is the core reusable idea.
A companion fixture to the rowspan test, verifying that `aria-colspan` is invalid when a native `colspan` attribute is present. It demonstrates a reusable negative-testing pattern for conflicting native-ARIA attribute pairs: concrete HTML examples, an explicit expected-checker verdict for each case, and references to the governing HTML spec sections. Another engineer could clone this page structure verbatim to build conformance fixtures for any new ARIA/HTML attribute-conflict rule.
A multi-vendor implementation status matrix that records, for roughly a hundred HTML elements and attributes, whether W3C Validator, ARC Toolkit, and IBM Accessibility Checker implement each ARIA-in-HTML rule. It uses a simple CSS-classed table (`yes`, `missing`, `filebug`) with links to tool-specific GitHub issues and external test cases. As a pattern, it is a reusable template for any standards body or library maintainer who needs to track per-rule adoption across multiple downstream implementers — it converts an otherwise unverifiable 'we follow the spec' claim into an auditable, issue-linked matrix.