In my plug-in electric hybrid car (Kia Niro), I engage engine braking by the initial press of the brake pedal. That initial braking is achieved by energizing the electric motor to act like a generator, thus charging the batteries. It's trading off some kinetic energy (speed of vehicle) for future potential energy (charge of battery).
The beauty of the system is that the regenerative braking, mechanical braking, electronic ABS, and stability control circuits work well together to form a seamless sensation of braking control in the car.
Of course, it all falls apart if the tires are bald and there is a sheet of wet ice on the road.
As far as I can tell, the internal combustion engine is not used for engine braking in this vehicle. Only the electric motor is used for engine braking.