File extension is used for some text documents, try to use text editor to open and edit.
Rexx is a procedural programming language that allows programs and algorithms to be written in a clear and structured way. It is easy to use by experts and casual users alike. Rexx has been designed to make easy the manipulation of the kinds of symbolic objects that people normally deal with such as words and numbers. Although Rexx has the capability to issue commands to its host environment and to call programs and functions written in other languages, Rexx is also designed to be independent of its supporting system software when such commands are kept to a minimum.
The EXC file extension is used in the Execs security software application to signify vault files that are locked by the program. Most text-based file formats can be saved using EXC file encryption, which can be opened and edited with the appropriate software.The EXC extension is also used in the Microsoft Office Word word processing program to signify the dictionary’s excluded files.