[Haskell-cafe] Visibility of definitions in Hugs Prelude

I am wondering about the visibility of definitions in the Hugs Prelude. More specifically, when I ask for info about the Eq class, I see a lot of instances, including:

instance Eq Key

On the other hand, Key is not in scope:

Hugs> :info Key Unknown reference `Key'

I imagine this has to do with importing/exporting, or maybe some modern Hugs empty-Prelude funkiness. Or perhaps it is because Key is a "non-standard export" (but that is just a comment in the Prelude). In any case, is it intended that ":info" will tell me about things that I (and it) can't otherwise see? Please forgive my naivete re module rules in advance ... . -- Fritz