JSLinux runs any disk image reachable over the network. You can find the Alpine sources over at https://github.com/alpinelinux. The Fedora sources are over at https://src.fedoraproject.org/. I don't think the script to package the pre-built images is documented somewhere, but it's all standard Linux you can install yourself in a virtual machine if you want.
The Windows 2000 sources are probably leaked somewhere on Github, or you could apply for a job with Microsoft maybe. I managed to get ReactOS to boot in JSLinux once by installing it into a standard QEMU image and splitting the image into chunks as required by the emulator code. You need quite a fast CPU to run a full, modern OS at acceptable speeds, though.
Where can I find the source code and instructions about how to make the Linux distro which runs here?
JSLinux runs any disk image reachable over the network. You can find the Alpine sources over at https://github.com/alpinelinux. The Fedora sources are over at https://src.fedoraproject.org/. I don't think the script to package the pre-built images is documented somewhere, but it's all standard Linux you can install yourself in a virtual machine if you want.
The Windows 2000 sources are probably leaked somewhere on Github, or you could apply for a job with Microsoft maybe. I managed to get ReactOS to boot in JSLinux once by installing it into a standard QEMU image and splitting the image into chunks as required by the emulator code. You need quite a fast CPU to run a full, modern OS at acceptable speeds, though.