When using Docker for Windows, you're actually using a tiny (custom) LinuxKit Linux running in a special Hyper-V VM. There's so much cool stuff happening, you're meant to forget it's still running on a Linux kernel.
Note this is about the default "Linux Containers" mode. It doesn't yet work for "Windows Containers" mode.
This is just a container that will have access to the Linux VM so you can do things like ps aux to see daemons running in the VM. It's not a full OS and I rarely have a reason to do this, but I get asked how to do it, so here ya go. Copy/paste from below or star my Gist here.