CML aims to be a lightweight downloader and patcher for ChroMapper. It utilises xdelta3 patches to minimise network usage.

It’s written in C# to be accessible to people working on CM.

The project has 3 sub-projects for Windows, Mac and Linux. Each has some code that is platform specific to allow the core functionality to tie into each.

Antivirus often flags CML as it downloads and runs theoretically arbitrary code but both CML and CM are open source (https://github.com/Top-Cat/CMLauncher) and the build infrastructure is public (https://jenkins.kirkstall.top-cat.me/job/ChroMapper/ ) so feel free to inspect the workings for yourself.