Fixed thermal Trip vs fixed magnetic trip current ratings
The thermal setting is a thermal overload protection. It has a time-delayed response. The heavier the overload, the faster it trips. It may be implemented by something like a bimetallic strip.

The magnetic setting is instantaneous short-circuit protection. It has no intentional delay. It may be implemented by something like a solenoid plunger, restrained by a spring.

Here is an illustration of a typical time-current curve  for a miniature circuit breaker (Clipsal 4 series) showing the thermal and magnetic trip characteristics. Note the thermal trip takes a long time - minutes or seconds - while the magnetic trip responds in 10ms or less.