Just kidding. It’s a bespoke shifter knob from EPCO – http://www.epcoshiftknobs.com/

Black with pearl grey racing stripes and 5-speed pattern. The thumb button is swapped from the US-market left to the right for use on the RHD Honda. Typically these are used for drag racing brake line-lock* or as a nitrous oxide* button, but here it’s being used as a “clutch switch” to tell the ECU to disengage regen when shifting.

* YouTube: Mustang Line Lock / Go Baby Go