[Haskell-beginners] Type explanation of foldl?

[Lawrence Bottorff]

I've got this

myFoldl f init [] = init
myFoldl f init (x:xs) = myFoldl f newInit xs
  where newInit = f init x

which when evaluated gives this for its type

> :t myFoldl
myFoldl :: (t -> a -> t) -> t -> [a] -> t

. . . not totally sure what that all means, e.g., how the t as a generic
class is behaving is very mysterious. Obviously, the final result is of
type t . . . and that must relate to the incoming argument init, correct?
(BTW, does a type declaration like this one reflect in any way the
recursion going on?)  But then with Prelude foldl I'm really clueless

> :t foldl
foldl :: Foldable t => (b -> a -> b) -> b -> t a -> b

I'm guessing the t is again a generic type of the Foldable class, but then.
. .  Can someone walk me through this?

LB
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