Non-reusable metadata extensions apply to single objects such as one source definition or one session. You create non-reusable metadata extensions in the Designer or Workflow Manager.
When you copy an object that contains a non-reusable metadata extension, the Copy Wizard copies the extension to the target repository with the object. The extension becomes non-reusable in the target repository. You can edit it, delete it, or promote it to a reusable extension. If the metadata extension contains a value, the wizard retains the value of the metadata extension in the target repository.