(4/5 if you are on legacy hardware).
: To test or calibrate a line follower module, you should place the sensors 1–2 cm above a white sheet of paper to see if the corresponding LEDs light up. Key Resources for mBlock 3.4.12 mblock 3.4.12
You cannot easily add new sensors. If a component isn't in the default library, you must manually edit the arduino folder inside the program files (a nightmare for teachers). (4/5 if you are on legacy hardware)