get_content
Description:
Gets the content widget of this.
This method should always be used instead of [method@Gtk.Window.get_child].
Parameters:
| this | an application window | 
Returns:
| the content widget of this | 
Gets the content widget of this.
This method should always be used instead of [method@Gtk.Window.get_child].
| this | an application window | 
| the content widget of this |