Full Impact

Full Impact was a spreadsheet program for the Apple Macintosh computer released by Ashton-Tate in the late 1980s.

File Identification
Full Impact version 2.0 files have Type  and Creator

Starting at byte 32 file header contains the string

Reference

 * Full Impact : Wikipedia
 * Choosing a Spreadsheet MacUser 1990 @ archive.org
 * NewYork Times 1988 Announcement