In A.2. Included Authorization Modules in Reference is table of included authorization modules. It should also contain line with code XACML and class org.jboss.security.authorization.modules.XACMLAuthorizationModule.
Moving to ON_QA. The changes should be available for review on the documentation stage within an hour or so from this comment. http://documentation-devel.engineering.redhat.com/site/documentation/en-US/JBoss_Enterprise_Application_Platform/
Verified on stage.