PDF/UA-1 (ISO 14289-1): a tagged document on PDF 1.7 whose structure tree covers every piece of real content (the rest is marked
as artifacts), with standard or role-mapped structure types, a title shown in the window, a determinable natural language,
alternate text on figures, header cells with a scope, links and annotations tagged and described, every font embedded and
mapped to Unicode, and the pdfuaid identification in the XMP metadata.
PdfUA1 = 1
ISO 14289-1, clauses 5 to 7 (veraPDF PDF/UA-1 validation profile; Matterhorn Protocol 1.1).