This is a custom Android and iOS app that can tweak your Metacycle. It works with a Bluetooth adapter and plugs into the USB charging port in the storage compartment. This is one method used to program the controller.
You can join the Discord server for more information. The device exists and is made on-demand by the developer (@metahack on Discord). You can purchase one through Buy Me a Coffee.
This is much more than the basic Votol Bluetooth adapter. It's a custom-built device that is powered by an Arduino. You can find schematics, case designs (OpenSCAD and STL), and additional information in the GitHub hardware repository. There's another repository for the Bluetooth to CAN bus software. It can be used to tune other Votol controllers besides the one in the Metacycle.