XML Inclusions (XInclude) Version 1.1 W3C Candidate Recommendation 30 June 2015.
Will not exit CR before 25 August 2015.
This document specifies a processing model and syntax for general purpose inclusion. Inclusion is accomplished by merging a number of XML information sets into a single composite infoset. Specification of the XML documents (infosets) to be merged and control over the merging process is expressed in XML-friendly syntax (elements, attributes, URI references).
The promise of XML of dynamic documents, composed from data stores, other documents, etc., does happen, but not nearly as frequently as it should.
Looking for XML Inclusions to be another step away from documents as static containers.