The Dataspace Protocol is a set of specifications designed to facilitate interoperable data sharing between entities governed by usage control and based on Web technologies. These specifications define the schemas and protocols required for entities to publish data, negotiate Agreements, and access data in a data space
The data object in 2.2 is a dcat:Catalog, not a dcat:Dataset. Even though dcat:Catalog inherits from dcat:Dataset, I guess we need an own schema for it.
The dataset reference in catalog/catalog.protocol.md needs to be fixed:
Response: Dataset containing the DCAT Dataset.
per @sebbader: