The import statement.
import Foo
--> Import "Foo Nothing Nothing
import Foo.Bar
--> Import "Foo.Bar" Nothing Nothing
import Foo as F
--> Import "Foo" (Just "F") Nothing
import Foo exposing (..)
--> Import "Foo" Nothing (Just ExposingAll)
import Foo as F exposing (..)
--> Import "Foo" (Just "F") (Just ExposingAll)