How does Deadzone/Anti-Deadzone work?

[gelpinator]

Can someone explain the controller deadzone settings to me. I'm having trouble finding information about them online.

Generally deadzone is expressed as a percentage or a decimal. How does the steam representation of deadzone relate? For example, what does a deadzone of 2000 mean on steam? Is that 2%?

Also for anti-deadzone, does that mean any controller input is padded or is the joystick input rescaled between the applied value and 100%?

Basically, I am trying to see what anti-deadzone setting to apply on a per game basis. Assuming a game has a 30% built in deadzone, what would be an optimal setting? Any help would be appreciated.