I saw it mentioned somewhere else, I don't recall where but it looked quite interesting. You can get it for £29 direct from the maker on their website
https://powerbug.pl The page is in polish but google translate takes care of that and the YouTube vids have English soundtracks.
I fitted it today and on the first spin of the wheel my iPhone went ping and started charging. I've not ridden with it but I'm looking forward to trying it out soon.
Mostly I expect I'll use it to charge a battery pack for recharging a phone/camera etc but I'm looking at getting dynamo lights at some point.