Sometimes it's a bit of both.
I built these at the end of 2000 for my 2001(plus a few more) season. Just some country hick in rural Queensland who looked at the tyre warmers of the period, didn't like what he saw, and had been playing with composites in toy aeroplanes for a few years previous.

During construction, carbon element sandwich between glass. Thermostat controlled, 300W @ 50Vac.

Controller just visible under stand. Also note how far they wrap around the tyres for heat retention.

Check out the dates when this UK company started working with the same idea and when it became a "product".
https://kippax-moto.co.uk/brands/thermal-technology/

I won't be making an IC/Electric hybrid any time soon though