EN 16931 is the European standard that defines the semantic model of an electronic invoice: which fields exist and what they mean, independent of the syntax they are written in.
PINT AE builds on this dictionary and adds the UAE rules. That shared foundation is why a package that already handles EN 16931 invoices in Europe is usually closer to PINT AE than one starting from scratch — closer, but not automatically compliant.
Official source: CEN — EN 16931