As you may recall, I moved all of the Virtualmin modules except virtual-server (which is the core Virtualmin module) into public github repos a few months back. At that point, we set in motion the underlying work to move the virtual-server module out, as well. This one was a much bigger undertaking, as the Virtualmin Pro code has historically been pretty thoroughly mixed up with the Virtualmin GPL code, and we had a script that would put together the right things into Pro and GPL packages when it came time to release.
Jamie's been fighting with it for some time, making Pro features modular, so they could be moved into their own directory (we needed it to not end up being two repositories containing almost the same thing, as that would be a maintenance nightmare...so, it needed to have little overlap between the two repos). And, last night he messaged me that it was done! So, I stayed up super late doing the git-fu needed to actually do the separation from the old repository and cleanse the history of Pro code. I gave up at 4am, while waiting for a BFG process to finish, but finished it up today when I woke up.
Note that source for Virtualmin GPL has always been available, of course, in the form of a tarball, but now our development repository is visible, so you can directly follow what we're up to, get the very latest development version (though be careful about tracking the git version...I wouldn't recommend it on a production system), make suggestions and pull requests, etc.
That was a long-winded way to say, it's live!
Please star it and stuff, if you're a github user. Feel free to browse our other repos, too! Every OSS Virtualmin module that we maintain is available there.