The lang and xml:lang attributes on <html> must match
readable/html-xml-lang-mismatch · WCAG 3.1.1 · Level A
The lang and xml:lang attributes on <html> must match.
In XHTML documents, if both lang and xml:lang are present, they must specify the same base language. Mismatched values confuse assistive technologies. Either remove xml:lang (preferred for HTML5) or ensure both attributes have identical values.
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Introduced in @accesslint/core v0.8.0