A question about Automotive failsafe IC ATA6842
Your answer is on the block diagram on the preceding page of the datasheet:



The linked IC provides several low side drivers (which you've already identified in the red box) in addition to a high side gate driver for driving an external high-side n-ch MOSFET. The capacitors are connected to the pin labelled BSC (Bootstrap Capacitor) for the driver's integrated charge pump. TCFET (Test Current FET) drives the gate on MTCFET1 (and on MTCFET2, see below:)



Issuing a command to the IC that turns on TCFET drives current from the net labelled K15 (battery voltage after the ignition switch, via. DIN 72552) into the current measurement comparator inputs through an external shunt resistor which, as JimmyB points out in the comments, is helpful for testing the functionality of the low-side drivers and/or other external circuitry connected to TCFET without activating the motor. The output of the comparator could then be measured by an external A/D to verify proper functionality before an error condition occurs.

The relays RL1 and RL2 change the direction of the motor. Driving RL1 pulls the "top" of the motor to K30 (the battery voltage, again DIN 72552) and RL2 pulls the "bottom" to K30.