This is root element of this document which contains name space definitions for the document elements. It's a referenced element. For detailed description, please refer referenced element doc. It's a referenced element. For detailed description, please refer referenced element doc. Description is not available. Unique identifier for the item. This field contains a number identifying the user-defined attribute. Provide an extension hook to customize ItemUDAFFRef. Provide an extension hook to localize ItemUDAFFRef. This type can hold a string of max length of 25 characters. This type can hold a number of digits count 5.