Over 1,700 pre-installed operating systems — from the 1948 Manchester Baby through Windows Longhorn betas, PalmOS, Plan 9, NeXTSTEP, BeOS, and early Android — bundled as a single Linux VM you can run in QEMU, VirtualBox, or UTM. Its virtue is completeness: a runnable history of every significant branch in the computing tree, not just the famous ones. The kind of preservation project that shouldn’t be possible but is.