The W3C just published a new TAG Finding called
This Finding addresses the question of how ancillary information (schemas, stylesheets, documentation, etc.) can be associated with a namespace.
I don’t quite understand why the TAG findings are hidden on some badly named Web page. Some of them are pretty interesting documents, and yet they are not published on the W3C Technical Reports page, and the W3C Home Page does not link to them or publish news snippets about new findings. I think these documents should be easier to find.
Technically speaking, the finding talks about how to create namespace description documents, so that namespace names can point to helpful resources, rather than being abstract identifiers. The TAG finding breifly describes possible languages for namespace description documents (RDDL 1.0 and 2.0 and GRDDL), and describes a vocabulary of terms for describing the nature of resources being linked to in a namespace description, and what the purposes of these resources are. The definitions of these terms, though, are one-liners with little guidance to what that concept is supposed to represent.
What I am missing most (and what we were concentrating on when we were defining our own format for namespace descriptions in an e-government scenario) is the ability to associate namespace descriptions themselves, and make assertions such
namespace x depends on namespace y. Or rather simple but really helpful pieces of information (in particular for developers) such as
namespace x is usually associated with one of these two namespace prefixes,
here is where you can find test data, or
here is where you can find some example data.