Packaging Issues

An unstarted project The XML Activity Statement promises work on packaging XML - providing descriptions of documents so that processors can determine whether or not they have the tools they need for reliable processing.
Different levels of packaging Packaging can operate on many different levels, from announcing which parts of XML 1.0 are used (CDATA sections? DTDs?) to whether or not external resources need to be retrieved (a problem with non-validating parsers) to whether Namespaces or Schema support is needed, to which Schemas and other resources are needed to process a given document.
An admission of defeat? The SGML declaration was one of the first things to get the axe when XML was created from SGML. Bringing similar packaging functionality back means that complexity has returned.
Growing demand As more and more pieces of the XML family of standards appear, it's becoming more difficult to exchange them generically.