Detecting a stall

Does Ardupilot detect if a plane has gone into a stall? if so, what does it use to do this? Does it use airspeed, pitch of aircraft or something else?

So I have read in the docs that ardupilot can’t detect stalls. If it thinks it’s going too slow then it will increase throttle. It also limits it’s roll to try not to make it get worse. It also pitches down 2 degrees without regard to its altitude. Sounds a bit random. Seems a bit of a contentious issue in the ardupilot world too…

Stall isn’t auto detected but if you know/work out the stall speed, then there are protections that can be set.