If the car is drive by wire it doesn't mean everything
There are some cars that are drive by wire where it's the accelerator only.
Brake by Wire
If it's an electronic brake system the term EBS or electronic braking system may be thrown around. As the article states EBS systems are typically found on commercial vehicles.
True brake by wire systems are in use in Formula 1 cars under the 2016 regulations. Honda and Chevrolet have hybrid brake by wire systems where some of the braking is done by electromagnets. If we are getting critical then we would consider those systems as more regenerative braking. Currently there are no brakes actuated by electric motors with hydraulics removed from the system but they are in development.
Steer by Wire
The only steer by wire system that is not a hybrid is the Infiniti Q50. There is no mechanical connection between the steering wheel and the front wheels.
Shift by Wire
Common. Think of paddle shifters.
Throttle by Wire
Very common. Some motorcycles too. Your foot depresses the pedal various sensors detect the desired amount of pedal and take into consideration wheel speed, RPM, etc to open a butterfly electronically in your throttle body.
All of the these systems go by the terminology of x-by-wire. The X being the variable of course.
Here is a great article on "How Electronic Throttle Control Works".