Cut & Paste
Cut & Paste was a word processor program produced by Electronic Arts, a company better known for its computer games, during a brief venture on its part into the area of home productivity software. Reviews found this software to be easy to use, but rather lacking in features; it didn't have such normal word-processor features as bold-faced, underlined, or centered text.
Its files were apparently pretty much plain text, given that there was little else you could do with the program, but Electronic Arts made the odd development decision to use a proprietary filesystem unconnected with the normal DOS of the target machine (versions existed for the Apple II, Atari 8-bit, Commodore 8-bit, and IBM PC), meaning that there was no manner provided to export, import, or interoperate with files between this software and any other program. There does not appear to be any documentation available on the specifics of the file and filesystem format.