Global lang-attribute validity (validity)
The global language attribute includes a valid language code such as for example, "en", "fr" or "fi" (ISO 639-1 Language Codes)
Invalid three-letter lang tag:
This page uses lang="eng", which is a three-letter
code from ISO 639-2. However, this format is not valid as a
primary language subtag in HTML, and therefore the
lang value is invalid and fails WCAG 3.1.1.
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