🧹 Clarification:

[nvartolomei]

Specification section

https://json-schema.org/understanding-json-schema/structuring#dollarref

What is unclear?

In the Modular Schema Combination the $ref documentation section https://json-schema.org/understanding-json-schema/structuring#dollarref contains the following draft specific note:

In Draft 4-7, $ref behaves a little differently. When an object contains a $ref property, the object is considered a reference, not a schema. Therefore, any other properties you put in that object will not be treated as JSON Schema keywords and will be ignored by the validator. $ref can only be used where a schema is expected.

It makes perfectly clear how $ref should be treated there but it is not clear how it the object with additional properties should be handled in newer drafts.

Proposal

Would be helpful to have the description in proximity for completeness.

Do you think this work might require an [Architectural Decision Record (ADR)]? (significant or noteworthy)

No

[nvartolomei]

This seems to be relevant https://json-schema.org/draft/2020-12/json-schema-core#name-distinguishing-among-multip. So ... application defined? 🤔