When I use the macro recorder on sorting a ListObject (table), it produces:
ActiveWorkbook.Worksheets(\"Output\").ListObjects(\"Table4\").Sort.SortFields.Add
This is not an answer; I'd like to add what I found out. Should have used comment maybe (but unable to).
Sort.SortFields.Add2 if you define a filter on either a ListObject or a Worksheet.Add2 method is not documented on MSDN for the SortFields Collection (1), but for serveral other objects (so "only for ChartObject" is not corrrect).Add2 as Function in SortFields Class; the only difference between Add and Add2 seems to be that Add2 has one more optional paramter [SubField].Conclusion: I guess (but this is only a guess!) that Add2 to is an expansion in functionality that has been implemented with a new name for compatibility reasons. Maybe the macro recorder always uses the most recent function in such a case.
Yor can use Add unless you need the SubField parameter.
I still like to get a deeper understanding, like Edwin Ederle asked for. I came across this post because of exact the same situation: using the recorder to learn about coding sort functions, wondering about Add2, and asking google. This question is (one of) the first google hit(s) if you search for "vba sortfields add2" => maybe worth giving some more information here.