AppleWorks
AppleWorks is a name used for three different office suites, one for the Apple II series, one for the IIgs (which didn't use any code from the earlier Apple II version, but could open its files) and a later one for the Macintosh (the latter being the former ClarisWorks, and more info on its file format is in the ClarisWorks article). Apparently the IIgs version could bridge the file-format gap between Apple II and Mac, since it could open Apple II AppleWorks files and its files, if ported to a Mac, could be opened in the Mac AppleWorks, even though those programs had different codebases.
Mac AppleWorks files are often found with .cwk extensions (inherited from ClarisWorks), though traditionally Mac users didn't save files with extensions because the file types were stored as metadata.