I'm not sure what you're asking about... The auto brightness is a feature natively built into Android for every phone with a light sensor or a front camera.
Auto brightness curve editor was a custom Rom feature available in the Rom specific settings (which would be the Evolver category in our case). I really don't remember which rom it was...
aah i see, i never take like a really deep look into those kind of setting. i thought the brightness curve editor is some kind of app that allows to modifies the phone brightness setting