Deprecating @copy-to

The @copy-to attribute is based on the way the DITA Open Toolkit is implemented, and makes some assumptions about DITA processing that are not otherwise (to my knowledge) mandated in the spec. Specifically,
 it assumes that a given input topic will, by default, be represented by a single referenceable output artifact; specifying @copy-to allows that output artifact to be copied (logically if not physically) to another referenceable location. I’d like to posit
 that any use case served by @copy-to would be better served by using keys.

 

Chris