I'd forgotten all about that file. When I first extended the ES/hour chart to cover two days, it was found to have a problem at the end of the month. In fixing that problem, I saved a special version of es_data.txt with that name, just to preserve the data in the event that my fix didn't work. I failed to add a pathname to the filename, so the file is saved in the current directory. I see on my system that it's saved in my home directory. In your case, the desktop has become the current directory.
In any event, the fix did work, so that precautionary file isn't needed. I'll remove that line of code for the next release.