WindowTitle is an option for Notebook which specifies the title to give for the window used to display the notebook.
WindowTitle->Automatic makes the title be the name of the file in which the notebook is stored.
WindowTitle->None displays no title.
The title given for the window need have no connection with the name of the file in which the window is stored.
Not all settings for WindowFrame leave room for a title to be displayed.
See Section 2.11.13.
See also: WindowElements.
New in Version 3.