Qt find main bar

Autodesk 3ds Max and Maya don’t expose their native qt widgets. But you can get them.

from PySide2 import QtWidgets

main_window = None
for widget in QtWidgets.QApplication.topLevelWidgets():
    if type(widget) == QtWidgets.QMainWindow:
        main_window = widget
        break
#print(main_window.findChild(QtWidgets.QMenuBar))
menu_bar = main_window.findChild(QtWidgets.QMenuBar)

see force tooltips in Maya to use tooltips