Meaning of thermal level on mac os

I can see the SMC tracks the computers thermal level in the console when I run

sysctl machdep.xcpm.cpu_thermal_level 

or

sudo powermetrics

the thermal level is different from the temperature, I would like to know what it means or how it is calculated. I tried asking here:

https://apple.stackexchange.com/questions/394244/what-does-machdep-xcpm-cpu-thermal-level-mean

related questions

https://apple.stackexchange.com/questions/251279/cpu-temperature-using-sysctl

https://apple.stackexchange.com/questions/54329/can-i-get-the-cpu-temperature-and-fan-speed-from-the-command-line-in-os-x/195937#195937