I believe it's often called the telematics module on wire charts. I don't know if unplugging it will void warranties or have other affects. Almost every new vehicle from 2016 forward (I think) has one, kinda bizarre.
Discussion
Definitely won’t void warranty, although I would probably plug it back in before you take the vehicle to a dealer for repair/maintenance. Also, if you have a vehicle that gets over the air software updates(mostly EVs for now), unplugging this will keep you from getting new updates
Any other adverse effects of unplugging the modem … other than software updates?
Depending on manufacturer, the modem may also provide geolocation data through a gps antenna. So if you have built in navigation in the vehicle, it will stop working. Also, if your car has any type of emergency call system like on Star, that will no longer function in an emergency.