It was Widescreen 3.07. I guess the question is why did it work before, since I added nothing new to the folder, and deleted nothing either. The only thing I can think of is I did not play the game using it, but that seems hard to believe.
This is impossible. Since running a setup-modname.exe creates a setup-modname.debug -file ... and likely the file that you had, is called "widescreen-v3.07.zip" or more likely "widescreen-v3.07.exe", which is self extracting archive file that you extract into the games folder... which adds the setup-widescreen.exe and a folder called "widescreen"...