I recently spun up a new server with 18.04 and EE v4, and moved a whole heap of sites over - fantastic and smooth transition! (thanks to all concerned).
I then installed Webmin, which seems to be running under nginx and NOT apache (I cannot find an instance of Apache). I did not expect this, but is a great outcome.
However, I cannot find the root directory for Webmin, which runs on port 10000 - where do i find this? Or where do I even look? I need it to install LetsEncrypt certificate.