was the autocenter confirmed on anything other than SideWinder joysticks
Yep
Logitech 'old' implementation: https://elixir.bootlin.com/linux/v6.16/source/drivers/hid/hid-lg4ff.c#L90
`new-lg4ff` implementation: https://github.com/berarma/new-lg4ff/blob/master/hid-lg4ff.c#L178
Logitech 'old' protocol: https://opensource.logitech.com/wiki/force_feedback/Logitech_Force_Feedback_..., page 15
Logitech implementation within 'hidpp' protocol: https://elixir.bootlin.com/linux/v6.16/source/drivers/hid/hid-logitech-hidpp...
iforce: https://elixir.bootlin.com/linux/v6.16/source/drivers/input/joystick/iforce/...
And that's it regarding devices 'in current kernel', excluding `hid-pidff` ones. Thrustmaster out-of-tree driver tmff2 has autocenter bit set as well (https://github.com/Kimplul/hid-tmff2/blob/e0a173f3265be8efcbd4a6f34df6c5713d...), and i think that on Windows autocentering property is set to `true` also.