You are reading the documentation for an older Pickit release (2.0). Documentation for the latest release (3.3) can be found here.
In this article the different settings of the Camera(s) tab are discussed.
One Pickit processor can be connected to two different Pickit cameras at the same time. This can be two M-cameras, two L-cameras or a M and L-camera combined.
Here you select which camera to use in the setup file. Each setup file should have exactly one active camera.
Robot camera calibration
Robot camera calibration is the process where the camera and the robot learn their relative position towards each other. If done correctly, the camera can guide the robot to correct positions in the physical environment. Once the camera and robot are mounted, calibration can be done. This process only needs to be repeated if the camera is moved relative to the robot base, or visa versa.