Qt.quit triggers Windows::closing signal

Calling Qt.quit triggers Windows::closing signal. Within the signal handler it's not possible to distinguish Qt.quit from user's attempt to quit app (like closing window or pressing alt+F4).

According to docs:

This signal is emitted when the user tries to close the window

Programmatic call to Qt.quit probably shouldn't be considered as an user action. Moreover in Qt 5 Windows::closing was not called on Qt.quit. The behavior is changed but documentation stays the same.