This was added to the KIP after the feature freeze.
If the property errors.deadletterqueue.context.headers.enable is set to true, the following headers will be added to the produced raw message (only if they don't already exist in the message). All values will be serialized as UTF-8 strings.
|__connect.errors.topic||Name of the topic that contained the message.|
|__connect.errors.task.id||The numeric ID of the task that encountered the error (encoded as a UTF-8 string).|
|__connect.errors.stage||The name of the stage where the error occurred.|
|__connect.errors.partition||The numeric ID of the partition in the original topic that contained the message (encoded as a UTF-8 string).|
|__connect.errors.offset||The numeric value of the message offset in the original topic (encoded as a UTF-8 string).|
|__connect.errors.exception.stacktrace||The stacktrace of the exception.|
|__connect.errors.exception.message||The message in the exception.|
|__connect.errors.exception.class.name||The fully qualified classname of the exception that was thrown during the execution.|
|__connect.errors.connector.name||The name of the connector which encountered the error.|
|__connect.errors.class.name||The fully qualified name of the class that caused the error.|