The way the content of $WILDFLY_HOME/docs/schema gets provisioned is very much a black art. The content is provisioned by the docs.schema Galleon package, which in turn is generated by the WildFly Galleon Plugin using occult forces an arcane process.

Add a comment to the various wildfly-feature-pack-build.xml files, before the 'package-schemas' element, that explains the arcane process. At worst we can point engineers to that comment when there are questions about this. I get asked about it a few times a year.

"When building this feature pack the WildFly Galleon Plugin generates a docs.schema Galleon package, which is used to provision the contents of the 'docs/schema' directory in a WildFly installation. To do this the plugin inspects maven artifacts that would be provisioned by the feature pack, looking for those whose Maven groupId matches one of the groupIds listed below. For all matching artifacts, the plugin checks for the existence of a 'schema' directory at the artifact root. If such a directory is found, the plugin copies out the directory contents and includes them in the feature pack as part of the 'docs.schema' package it generates."