KF-PDF-AF: The attachment is not declared in the catalog
This code shows up when an electronic invoice is validated. Here is what it means, why it fires, and what to change in the file.
Why this code appears
The attachment exists in the name tree, but the document catalog does not list it in its /AF array. A reader that follows PDF/A-3 will not see it.
How to fix it
Add the associated file reference to the catalog's /AF array. Most PDF libraries do this automatically when you use their PDF/A-3 attachment function rather than plain attachment.
Where it happens
This check is ours, not a code from the standard: we do not cover enough of EN 16931 to borrow its numbers, and a misattributed official code would send you to fix the wrong field. It concerns PDF.