Considerations for removing classification map and classification domain

[Kristen James Eberlein <kris@eberleinconsulting.com>]

I want us to think about removing the classification map and the classification domain. We'd move them into the new GitHub repo.

Reasons for removing the classification map and domain:

• It's impossible for authors to use.
• I don't think anyone uses it, except perhaps Zoomin behind the scenes. For the most part, Zoomin has implementations create a speadsheet which they then build classification maps from, I think.
• We have the idiocy of shipping the classification domain in the base, but it's only integrated in the technical content shell for map.

Reasons for NOT removing the classification map and domain:

• It's the only standard-defined mechanism for associating subjects with <topicref> elements

One possibility would be adding an attribute to <topicref> elements, let's call it @subjectrefs, but that would be yet another abuse of how keys work. We'd need to explicitly define what we would expect processors to do when they encountered a @subjectrefs attribute.

Thoughts?

--
Best,
Kris