Using Schema XDOC 2.0

The XDOC XSD is located here.

Your favorite IDE probably supports XSD schema's for .xml/.xdoc files. You need to specify the following:

<document xmlns="http://maven.apache.org/XDOC/2.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/XDOC/2.0 https://maven.apache.org/xsd/xdoc-2.0.xsd">
...
</document>