SPEC.MDB links the FCnnn files as tables in a Microsoft Access database. If you open spec.mdb with Microsoft Access, you should easily get an idea of the ways you can use this information. In this database you have zero, span, limits, tuning parameters, and so on - all the specs and block numbers in the whole system.
To use these FCnnn.DBF files in any other structure, you should copy them from where they are created, as the FCnnn.DBF files cannot be appended to if active.