Documentation for thermostat modes?

I noticed that since official integration/support between nest and smartthings, there are quite a lot of options under the “mode” and “fan mode” settings. For example, under “mode” I can select:
Auto with Eco
Auto with Reset
Auto Changeover
Auto Changeover Active
Auto Cool
Auto Heat
Auxiliary Heat Only
Auxiliary emergency head
Day Off…

And a ton more. I haven’t been able to find any documentation to describe what these settings actually do, and more specifically how they would interact with a Nest thermostat. Some are pretty obvious, but others (Southern Away, I’m looking at you) not so much. Would anyone be able to point in to the relevant documentation for these features?

You may want to search for the documentation at Googlle Nest as they maintain and manage the integration with ST.