This says nothing about any auxiliary lights you choose to mount, though. Still, I guess this thing would be illegal in Germany simply due to the fact that lighting on a vehicle is very rigorously specified and I guess the green colour won't fit well with the laws here.

I guess I'll opt for a very bright (hub) dynamo-powered light instead, but my main concern currently is not visibility but that I can still see the ground when there's a car coming at me with blinding lights.

(Side note, anecdotal evidence: No cyclist I know ever had problems with the police for using battery-powered lights instead of dynamo-powered ones. Most of the time they're happy when cyclists have light at all.)

Indeed, battery powered lights can be problematic (due to 70 year old laws...).

But a powerful LED light source is great as an additional gadget. (Although, at 4-6m range, this item is not sufficient to illuminate the road ahead).