Json Schema for Relationship Models

Continuing the discussion from SME: Relationship Model - Orderable flag gets serialized to the other role in model JSON:

Please confirm the json schema with respect to the orderable flag set in the Relationship Model Editor in the SME.

I have created ticket A12-18850 as way how to improve modeling and usability of relationship models. Current mismatch between what is done in SME and what is expected in DS is creating unnecessary complexity.