Until now the Polish KSeF (FA(3)) rules in einvoice-preflight were tested on one hand-made invoice and its planted-defect twin. This run checked them against files the Ministry of Finance and CIRF publish in their own client repositories: 14 distinct sample invoices, with their #placeholders# filled in.
Result: the schema gate agrees with xmllint on the real XSD on all 14, and 12 draw no finding, so no false positives on files KSeF's own tooling produces (attachments, self-invoicing and third-party subjects included). The other two are rejected by xmllint as well: the Ministry's templates put IDWew and Nazwa in the wrong order, and we report that as PL-013.
Limits: templates, not invoices a company issued, and only the plain-VAT branches. Correction and advance invoices still need real files. The repeatable script is eval/ksef-official-templates.mjs.