Optional. Required for UserData uploads. The encoding type of the user identifiers. For hashed user identifiers, this is the encoding type of the hashed string. For encrypted hashed user identifiers, this is the encoding type of the outer encrypted string, but not necessarily the inner hashed string, meaning the inner hashed string could be encoded in a different way than the outer encrypted string. For non UserData uploads, this field is ignored.

Optional. For testing purposes. If true, the request is validated but not executed. Only errors are returned, not results.