resumeIn brief
It is not the same as the pedal boost.
Useful to know
The main cylinder converts the applied force into hydraulic pressure in the braking system. Bosch describes its function separately from wheeled cylinders. [1]
The amplifier assists the effort, but it is not just another name for the master cylinder. With an unclear pedal feel, the exact distinction is useful for describing the system. However, it is not a remote diagnosis. A similar symptom can have different causes and requires a procedure for the specific performance. A cylinder is not selected only by the general model of the car or close appearance.
Sources
For further detail and to check the information: