Not much here, I think I fixed pymclevel, so here are some standalone executables so you don't need to install Python 2.7, which is deprecated, and all the modules needed. Theoretically you don't need to install anything, it runs as is. I only created these executables though, so if you are on Mac or if you have a different CPU architecture, you might need to run the source code using Python. There are two versions, so choose the right one depending on whether your world uses anvil format or not.
Usage
/!\ These are command line executables, meaning you do NOT double click them to run them, your run them from your terminal /!\
Linux :
./mcmerge-pre-anvil-x86_64-linux trace /path/to/your/worldWindows :
mcmerge-pre-anvil-x86_64-win.exe trace C:\path\to\your\world