i always thought it was that Swiss guy living in Tokyo
Yet even before crypto was a thing, Germany always had a thriving community of people concerned with privacy, hell, even the average german prefer to pay in cash to not be tracked. We have CCC and so on.
About the gmx email: I've seen people from abroad using those gmx emails, mainly in the security space. I find it funny because gmx is kinda crappy, full of ads.