As reported on Homepage
GM has issued the following service bulletin for 1) HVAC system reprogram, 2) rear spoiler fastening, and 3) engine harness inspection/repair.
The reprogramming of the HVAC system is to prevent HVAC evaporator freeze-up after extended highway drives. The rear spoiler service is to fasten the (sometimes loose) nuts used to attach the rear spoiler to the trunk kid, and only applies to VINs A9126194 or lower. And the engine harness inspection ensures that the heater hose clamps are not touching the harness bracket.
Though these are not recalls or critical services, it's suggested that if/when your car is in for service or maintenance, to have these services performed (if applicable).