Beside of users and groups does SCIM covers CRUD operations for other resources. I guess no ? Mean on custom resources for specific cases. Per instance custom Product resource to be provisioned between two trusted SPs.
The only one extensibility (correct me if I am wrong) dictated by SCIM default schema is Enterprise User ("urn:scim:schemas:extension:enterprise:1.0")
Yes, only users and groups are covered by the spec, but as you mentioned you can always add extensions.