From Just Solve the File Format Problem
FullWrite Professional was a word processor application for the Apple Macintosh, released in late 1988. Originally developed by Ashton-Tate later sold to Akimbo Systems in 1993.
FullWrite version 2 has Type
FWRI and Creator
FullWrite version 1 has Type
FWRT and Creator
The last 5 bytes of each file are hex values
01 46 57 52 54 which is ASCII " FWRT"