The wpcrm_system_gdpr_export_get_data filter functions exactly the same way as wpcrm_system_export_get_data.

However, the wpcrm_system_gdpr_export_get_data filter is only used on the GDPR export. This allows you to filter the data that is included in the export to your contacts. Use this along with wpcrm_system_gdpr_export_cols_{export-type} to ensure that columns and data are aligned correctly.