Earlier quoted context omitted.
I always found Kubernetes API reference very useful.
Yeah, that part was always fine, but they sorely lacked a theory of operations -- which is essential for any sort of state machine or orchestrator! -- and basic "man page"-type documentation around processes, config files, etc.
They are also not operating system user interfaces, productivity tools, games or web-browsers, and so not the topic of my little sub-thread here.