`Ellipsis` is one of the few builtin objects whose type is not exposed via the `types` module. 
This is not really an issue during runtime, as you can always call `type(Ellipsis)`, but for the purpose of typing it is detrimental; the lack of suitable type means that it is impossible to properly annotate a function which takes or returns `Ellipsis` (unless one is willing to resort to the use of non-public types: https://github.com/python/typeshed/issues/3556).

In order to resolve this issue I propose to reintroduce `types.EllipsisType`. This should be a fairly simple process, so if there are no objections I'd be willing to give it a shot.