Lockout Switch Feature
WARNING: This page is about a different car, the 2020 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
The driver front side door window control switch contains a window lockout switch, when the driver presses the window lockout switch, a serial data message is sent to the BCM which will send a disable command to the rear side door window switches, deactivating them. The rear windows will still function normally from the switches on the driver front side door window control switch.