jack wrote:
....
I thought the winter blend had higher volatiles to make cold starting
easier. ...

Basically, yes, for climates where it's cold enough to really make any
difference. Much of the US really doesn't get cold enough to matter much.

I'm not all that certain what specifically is in the "veritable
plethora" of various blends required for the specific EPA and
state/local mandates for pollution controls. Ethanol is one component
of many...

--