lib/rules/html-lang-valid.json

{
  "id": "html-lang-valid",
  "impact": "serious",
  "selector": "html[lang]:not([lang=\"\"]), html[xml\\:lang]:not([xml\\:lang=\"\"])",
  "tags": [
    "cat.language",
    "wcag2a",
    "wcag311",
    "TTv5",
    "TT11.a",
    "EN-301-549",
    "EN-9.3.1.1",
    "ACT"
  ],
  "actIds": ["bf051a"],
  "metadata": {
    "description": "Ensure the lang attribute of the <html> element has a valid value",
    "help": "<html> element must have a valid value for the lang attribute"
  },
  "all": [],
  "any": [],
  "none": ["valid-lang"]
}