Reference guides are technical descriptions of processes or products that users can study. Reference guides are designed to be "information-oriented" and their primary function is to describe.
These docs may also include some usage steps in the course of description; however, their purpose is not to explain concepts nor to outline steps to achieve tasks.
The users who utilize reference guides are knowledgeable with the Rancher product as well as how to use it. They will benefit from detailed descriptions of something to be used when needing to refer to specifics of usage.
Good examples of Rancher reference guides would be the Rancher Manager architecture and cluster configuration guides.