RE: [xliff] possible issue with URN prefixes used to define acceptable namespaces in XLIFF 2.1

[Yves Savourel <ysavourel@enlaso.com>]

One more note on using a namespace specific to the module:

It looks like we will have to have the ITS namespace involved because some data category information like mtConfidence or
taConfidence MUST have its:annotatorsRef set, and ITS does not provide any mapping mechanism for that.

Currently 2.0 defines "XLIFF-defined" constructs are constructs with a namespace starting with "urn:oasis:names:tc:xliff:" (except
for pre-2.0 namespaces).

It also says that XLIFF-defined constructs MUST be preserved and other constructs SHOULD be preserved. So the ITS module's
attributes would be preserved for sure, but the accompanying annotatorsRef may not.

So, in summary: a tool not supporting the ITS module may break the validity of some features of the ITS module. And do that while
being conformant to the processing requirements.

The solution would be to add "http://www.w3.org/2005/11/its"; to the list of namespaces that MUST be preserved. But if we do that we
change the expected behavior for the Core and 2.0 tools will have to be modified to handle 2.1.

Any ideas, anyone?
-yves