I can't figure out how the Calibration curve work in the calibration settings page.

Running Android I always get non linear values regardless of what calibration settings I choose.
Running Linux I always get linear values.

Is there any special "magic" that I have to do the change the calibration curve?

your using the same controller for both? Not all controllers are the same. Also, while I dunno if you can set the type of curve on android, PC pilots can set the curve applied to their joysticks. Options>controls>joystick; its near the top of the page.

Thanks for the report. The current state of those settings is incomplete and the feature was released prematurely.
The settings work in Windows and iOS but not on other platforms.
On Linux and Mac, the settings are always "Linear", and on Android it's always "Default Gamepad".
Sorry about the problem. We'll try to clean that up soon.

Thanks for the feedback. Looking forward for the update.

Any ETA on the update for this issue?

Hopefully this is something we can roll out in the next few weeks. We had some releases encounter unexpected bugs and problems, which has delayed other projects.