The layout it's close to /sys/doc for 9front/plan9 with guides for Acme, Sam editors (the guide to structural expresions as a tutorial and a guide), the Rc shell, the kernel, the ACID debugger, FS' (several, fossil/venti, cwfs and now GeFS), the security, the compilers, the Rio window system, namespaces, processes and channels, plumbing (something like xdg-open but far easier and more powerful), ... much more than a closed source and propietarty NT implementation, as you get the source for free too under libre licenses. Thus, it makes debugging the system a far easier task. And it's far simpler than Unix itself too.