An electrical assist applies power in proportion to your own pedalling. Some ebikes have a twist-grip throttle in addition to or in place of pedal assist. The Felt does not.
Bosch boasts of three-sensor integration in their proportional power control. I'm guessing these are pedal pressure, pedalling rate and perhaps gear or gear shifting.
I was attracted to the smoothness of the Bosch power control. Less sophisticated bikes switched power on and off suddenly creating a jerky ride. The Bosch feathers assist on and off slowly. It has taken me some time to understand and anticipate when the drive will switch control parameters.