The XML validation relies on multiple XSD files.
The main file for most recent versions of the product is IntroscopeManagementModules4.0.xsd. This file has local dependencies on its.xsd,xml.xsd and xlink.xsd
The schemas for older versions of the product are in the same folder. Check the top of the ManagementModule.xml in case it refers to a different version of the schema to use:
All files are provided inside com.wily.introscope.em_x.x.x.jar , where the x will be replaced by the version of the product you are using.
You can extract the data from the jarfile using the jar command
jar xf com.wily.introscope.em_x.x.x.jar
This will provide a directory structure to find the files, you will find it based on the fully-qualified name:
So, the folder would be com/wily/introscope/server/enterprise/entity/bundle
For online validation, most sites only accept one XSD file but this site allows you to add XSD files as their dependency is discovered.