Talend offers custom policies that can be used within the Talend ESB, for example: the Correlation ID policy, the WSDL Schema Validation policy, the Custom Schema Validation policy, the Transformation policy, and the Compression policy.
However, those policies are only available in the Talend Enterprise and Talend Platform products. They can be find under the add-ons\registry\policies directory of the Talend ESB delivery, and can be uploaded to the Service Registry via the Talend Administration Center Web User Interface (for more information, see Talend Administration Center: Concepts and Principles), or via Service Registry commands (for more information, see Using the Service Registry with Talend ESB).
Those policies can also be enabled by declaring the corresponding feature. For more information on how to enable some of them via feature, see the following sections.