EN 301 549.
The European standard that most EU accessibility obligations point at.
What it covers
EN 301 549 is a broad standard for ICT accessibility: hardware, software, documents, support services and web content. Its web chapter incorporates WCAG Level AA essentially wholesale, which is why meeting WCAG AA is the substance of meeting it for a website.
It goes further than WCAG in places, with requirements for things a web standard does not cover — real-time text, two-way voice communication, and accessible documentation and support.
Where you will meet it
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A real report on your real templates. Yours to keep, whatever you decide next.