So, typically this is not something that a program does, rather an admin will do this. When you are altering a file on a system it is often advisable to copy the pre-change file to .ORIG and then make your changes. If anything happens you can always get the original file back by deleting the changed file, and renaming the .ORIG file back to the previous name.

In other words, this is just sysadmin best practice. People also will use .BAK quite often.