How mixer works

Hi all,

I have been looking into the px4 mixer. I do find some useful posts on the forum. But I am still confused about the mixer working pipeline.
To my understanding, fmu subscribe the actuator_control topic and store it in _controls[]. As you can see here, fmu.cpp.
How exactly it is changed into pwm_limit[] after the do mixing part?
Is it related to the mixer structure or something?
Thank you for any insights.

@bresch Could you please share some insights?
Thank you very much.