Are you a developer an you found the registry interesting? You can get the collections through known protocols for editing.
The schema on which the registry was developed is DCAP. For more information on this visit here.
One of the most well-known protocols for harvesting metadata is OAI-PMH. For more information on this visit here.
You can harvest all the collections of the registry through the following link:
To harvest a specific collection, you can do so in the following link, using the unique identifier of each collection: