My proposal for what to do with the classification domain

I propose that we do the following: Remove the classification domain and classification map from the base package.
Add the domain and the document-type shell to the repo for things removed from the spec.
Add a new attribute, @subjectrefs, that would be available on <topicref> and <topicref> specializations.
We probably won't want it available on all the specializations of topicref used in bookmap ...
Do not include processing expectations for @subjectrefs in the DITA 2.0 spec; that would require more time and consideration than we have at this point in the DITA 2.0 development process.
However, adding the attribute for DITA 2.0 would open the door to specifying processing expectations in future release.
Because we would be adding a new attribute, this would require going through the proposal process.

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Best, Kris