From BR Wiki
Internal Data Files in Business Rules! contain a header that may range from 16 to 256 byes.
The first 16 bytes of the header describe the table.
Byte Position Data Type Description POS 1 B 4 Last Record in the table POS 5 B 4 File Version POS 9 B 1 File Type (4 = Internal) POS 10 B 2 Record Length (Remember that this does not include the "Delete Byte" POS 13 B 2 Header Length. Data starts at the next byte. (Note: The header length is usually the same as the True Record Length until the max value of 256)