(Header) : KSeF QR code

A KSeF QR-code is a machine-readable graphic symbol printed on a Polish structured invoice that contains a verification link pointing to the invoice stored in the National e-Invoicing System (KSeF).
It encodes a URL that allows the recipient to quickly check whether the invoice exists in KSeF, verify its authenticity, and download its structured XML, even if the invoice was delivered outside the platform (e.g., PDF or paper).