Missed XSD Schema for the file webapp-cache.xml

When packaging a web-application, maven-war-plugin generates a cache file, as described here: http://maven.apache.org/plugins/maven-war-plugin/exploded-mojo.html#cacheFile

This cache file is an XML file but the generated file doesn't contains an Schema or DTD declaration on its header. This makes impossible to validate such file, generating warnings in the most common Java IDEs. Since it is a mandatory XML file I believe it should has a model specification somewhere (a XSD Schema I hope), eventually just not released for public usage.

The steps I expect to make Maven 2 WAR plugin better:

• to modify the generator of the webapp-cache.xml file to include the proper XML header (with namespace and schema location)
• to make the schema of such file publicly available, in order to give the developers and automatic tools a chance to validate any error in a deployable artifact.

This will give us a chance to detect potential bugs before to deploy a web-application.

----------- The expected header is something like:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<webapp-structure xmlns="http://maven.apache.org/plugins/maven-war-plugin" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/plugins/maven-war-plugin
http://maven.apache.org/???/???.xsd">
...
</webapp-structure>