over current trip switch in LV breaker

I don't entirely follow your description.

If it is a typical thermal magnetic MCB (Molded case Circuit Breaker) then the unit will have both a thermal over current trip unit and an instantaneous magnetic trip circuit.

Auxiliary switches then usually indicate the status of the breaker for other control circuits.

Optional features may include shunt trips to allow an external circuit to trip the breaker.

Your catalogue number, make, name plate data etc. would allow a "google" of what you are actually looking at.

The OTS switch function is to provide a signal to indicate the breaker has tripped open by action of the electronic trip unit due to phase or ground overcurrent, which is why it does not show up in the electrical schematic trip circuit.

The NC contact you see in the schematic close circuit is a block close of circuit breaker. This requires technician to investigate fault and manually reset OTS switch before circuit breaker can be returned to service.