While the seller claimed it to be a EU plug it turned out to be only compatible with the other part of the EU - it won't work with the ground pin of the CEE 7/5 socket.
I got a refund from the seller and kept the product. Since it's not usable anyway (apart from the cables) I looked inside.
Then I was able to pull the insides out of the box
I guess there's no room for the ground pin there :-)
The PCB contains standard parts - Vishay MB6S bridge rectifier, Sharp PC817c optocoupler a power NPN 13003, a bunch of capacitors, diodes, resistors and a transformer.
I'm not desperate enough to repackage it to work with my sockets ... yet.