If by robotaxi you mean the vehicles used in the tesla test in Austin and now in the bay area, they are just regular model y with an emergency "stop so you don't kill me button" on the right side. They have a special version of the software that is unreleased. The current model Y's / "robotaxi" have all the regular hardware, including pedals and steering wheel and sensors. If you search, you can even find cases during the Austin Texas where the safety drier gets into the driver seat in a few situations.
We don't really know what a special robotaxi hardware would look like.