In GKS-Core 1.0.0, primaryCode was renamed to primaryCoding and is now a Coding.

However, CopyNumberChange still references the old version in the description as seen here.

I'm assuming we would represent as:

{
    "code": "0030069",
    "system": "http://www.ebi.ac.uk/efo/EFO_"
}

The validation tests also use this old version (https://github.com/ga4gh/vrs/blob/2.0.0/validation/models.yaml#L374-L375), but somehow the tests are still passing?