"Rule as Code"-type of queries for extracting the relevant information from the SAF-T Example: XLST? Example from VAT in Norway: Published formal validation rules, see more: https://skatteetaten.github.io/mva-meldingen/documentation/forretningsregler/#valideringsregler Example from Peppol: Peppol have been using principles and tools for automatic testing of software ot support automatic validation of peppol formats