A field reference file is a normal IBM i database file that is created for use as a data dictionary.
Typically a field reference file contains the definition of every field used by an installation. The field reference file never actually contains information (records) itself, it is used as a common reference point for the definition of fields used in other "real" database files that are created.
Since field reference files are very widely used, a facility is provided that will create a field reference file from the LANSA data dictionary.
It should be noted that a field reference file created by LANSA has no use whatsoever within LANSA. The facility is provided purely as an aid to applications that are external to LANSA and provides a means of centralizing and standardizing the methods by which data dictionary(s) are maintained on the IBM i.