PDF/A-4 (ISO 19005-4:2020): based on PDF 2.0, so the file has a %PDF-2.n header and no 1.7 limit; the identification
names the part and the revision year (pdfaid:rev 2020) and no conformance level; the trailer has no document information
dictionary (a save moves its entries to the XMP packet), unless the catalog has PieceInfo, when it keeps only
ModDate. Every font program embedded, an output intent, no encryption and no forbidden actions, as for PDF/A-2. An
embedded file must itself be PDF/A-1, -2 or -4, which a save does not verify, so it reports any.
PdfA4 = 5
ISO 19005-4, 6.1.2, 6.1.3, 6.7.3 and 6.9 (veraPDF PDF/A-4 validation profile, rules 6.1.2-1, 6.1.3-4, 6.1.3-5, 6.7.3-2 to 6.7.3-5, 6.9-3).