They obviously wanted data from Riseup, about some email address. Which I gather has no presence in Germany. So they went after Zwiebelfreunde.

That seems ridiculous. I mean, there's no way that Zwiebelfreunde would have any data about Riseup's email accounts. Even Riseup claims to retain nothing.

I suppose that Zwiebelfreunde might have handled contributions to Riseup from someone using the targeted email address. So there might be a money trail. But that's pretty iffy.