Extensibility with the Data Dictionary means data providers can create new local fields to address specific needs that are not currently covered by the Data Dictionary and still be in compliance with the standard. Omissibility allows data providers to exclude fields that are irrelevant for their business needs from their technology implementations. These features ensure that the Data Dictionary can meet the needs of diverse organizations without compromising the standardization of core data elements.
More Info on Extensibility & Omissibility in the RESO Data Dictionary
