expressjs middleware next function vs response objects next function

I recently noticed an undocumented next function on the expressjs response object.

Is that function the same as next in the middleware function(req, res, next) ?

Is its use discouraged because it is undocumented?

Yes, it is the same function as can be seen here in the source code.

Yes, I would say it's use is discouraged because it is undocumented and also unnecessary since each middleware function will get next passed in as the 3rd argument.