FX-AF2 rules
Whether the PDF declares the invoice as an associated file at all. Get this wrong and a compliant reader never looks for the XML, however perfect the XML is.
| FX-AF-01 | warning | The PDF catalog must reference the embedded invoice in its /AF (Associated Files) array. |
| FX-AF-02 | warning | The embedded invoice's /AFRelationship must be /Alternative. |
Nothing is stored, and the whole invoice is checked, not just this rule. A PDF only works if it is Factur-X / ZUGFeRD — a PDF with the invoice XML inside it.