Note: Heavily updated
I'm in charge of this. For the new version 12, I used last weekend to completely restructure the code and move it to a new repository:
I spend a good amount of time to document how it works and to prepare examples and tests. The final highlighter script is either
lang-mma-alternative-regex.min.js and the README explains the difference in detail.
If you clone the repository, you can directly try the highlighter by opening
JSHighlighter/index.html locally. If you have some knowledge with the Chrome developer tools, you can also use local overrides to try it on the live StackExchange site.
It would be great if some other users could look over it and try it before I make a release. After that, we need to bug SE staff that they update the script for our site. We learned that their workload is currently high, so we should not expect a quick solution though. But we can ask.