The file you're looking for is in C:\Attract\Romlist\
If working with MAME, you're looking for mame.txt
I've got a subdirectory under that directory, but the file is not there, it's in C:\Attract\Romlist\
I have tried editing it with Excel, and LibreCalc. I've had MUCH more luck with LibreCalc. When you open it up highlight the corner of the opening screen (see circle on image), and change the Column type to "Text". You have to open and save it as a CSV separated with semicolons, and save it as a CSV then rename it to .txt.
Oh, you can edit the categories et.al. from there.
Hope that helps!