First, download the .zip file, extract livesets.py from it, and put livesets.py into a directory containing your Montage files.
Then you will need to install a Python interpreter. You can download a Windows one from here, or a Mac one from here,
For Windows 10, I suggest you download the 64-bit version. It probably wouldn't hurt to download the 64-bit version for a Mac as well.
Once you have the Python interpreter installed, open a command-line window (cmd.exe or PowerShell on Windows, Terminal Window on a Mac), navigate to the directory containing your Montage file(s) using the 'cd' command, and type this:
The app will print instructions for how to use it.
At the moment it prints Live Sets in outline form. In the future, I'm thinking I might have it print in a grid form that matches what you see on the Montage Screen.
I've only tested it with .X7U files. It will only work with files created with version 2.0 or later of the Montage firmware. I might extend it to work with earlier versions.
If any of you use it, let me know how it goes. I'll be happy to look into and fix any bugs you find.