DSC configurations only make sense when you configure resources with your configuration. All of the resources referenced in a configuration have certain key properties, mandatory and optional parameters, and read-only parameters.
Key properties are important, as they ensure that resources are not configured with conflicting settings. You would not, for example, be able to configure two file resources with the same destination path.
It is not only the key property of a resource that is unique; the resource name is unique as well, and consists of the resource type and the resource name. [ResourceType]ResourceName would, for example, become [File]SomeFileResource.
When using partial configurations, these key properties can only be validated once the configuration is assembled on the target node, which is why we strongly advise against using partial configurations.