Message from the owner(s)
Version 1.0 has been released. Features:

Schema JAR archetype for easier creation of schema JAR projects
Two schema JARs to validate Struts 1.3 and J2EE 1.4 (partial only at the moment) are available in the main download (these will be separate when deployed to the Maven repository). After downloading you can now immediately start validating your Struts configuration and J2EE web descriptors.

To install, download from the Documents & files section and unzip into your local Maven repository (typically the [user home directory]/.m2 directory). Eventually the plugin will be uploaded to a proper repository so this will not be necessary.