https://mail.gnome.org/archives/xml/2009-September/msg00022.html
Re: [xml] Support for embedded Schematron in XSDs
support forxmlembeddedschematron
https://www.ercot.com/services/mdt/xsds
XSDs
XML Schema Definitions (XSD) files are used to define extracts provided in an Extensible Markup Language (XML) format.