That may be so, but GitHub has an individual file limit of 100MB, and practically speaking, most people don't want/expect to open a 150 MB text file in their browsers, so I think this is a good compromise (though it might be worth being extra clear in the readme that the malbolge source is in the archive)
Quoting the readme:
> What is inside the zip file?
> The release bundle includes interpreter binaries [...]. malbolgelisp-v1.1.mb is the source code for the interpreter.
The way I parsed that when I first read it, I took it to mean that the filename of the lisp interpreter was "malbolgelisp-v1.1.mb" and was somewhere else in the repo, not in the 7zip archive with the interpreter binaries. I see what it means now, but the two ideas felt disjointed on my first reading.
