The documentation clearly says it's a list of all methods including inherited ones.
Yes, but documentation shows only public method, and also should show inherited public method.
It's just reimplemented as private so
Where it is written?

you don't have a stupid idea of calling it and segfaulting your application on the first reference to the widget.
For you knowledge, you can't compile program where you use virtual method reimplemented as private!
And I have a favour to ask of you Can you be more polite?