“quickget automatically downloads the ISO image for the operating system you want to run and creates a configuration file for the virtual machine.”
QEMU can run almost anything, and its command line ensures almost nobody does. Quickemu wraps it in two commands, one to fetch an OS and one to boot it. That includes macOS, which Apple would rather you didn’t run off a Mac. A shell script did what the hypervisor’s own developers never bothered to.