Inconsistency in markup + xml mention domains

Hi,

I've been making my way through the tech-comm updates making updates for DITA 2.0, and noticed an inconsistency in the DITA 1.3 spec. The <markupname> element (specialized from phrase) and the XML mention elements (7 elements specialized from <markupname>)
 all state that they use the universal attributes + outputclass + keyref:

http://docs.oasis-open.org/dita/dita/v1.3/errata02/os/complete/part2-tech-content/langRef/technicalContent/markupname.html

http://docs.oasis-open.org/dita/dita/v1.3/errata02/os/complete/part2-tech-content/langRef/technicalContent/xmlelement.html

However, in the DITA 1.3 vocabulary files, they don't define keyref:

https://github.com/oasis-tcs/dita/blob/master/doctypes/rng/technicalContent/rng/markupDomain.rng#L67-L72

https://github.com/oasis-tcs/dita/blob/master/doctypes/rng/technicalContent/rng/xmlDomain.rng#L181-L186

We need to fix this for DITA 2.0. Either of these options is valid for the new release; should we:

Add keyref to these elements (update 2.0 to match the 1.3 specification prose), or

Remove keyref from the spec (update 2.0 to match the 1.3 grammar files)

Thanks,

Robert