The Dutch police imaged the drive, gave it to the Americans and gave the server back to XS4ALL which itself appears to have shutdown too I think
Xs4all was owned by KPN, but was an independent daughter company. They got merged fully merged with KPN a little less than ten years ago. The article mentions DC1 is a successor of Xs4all's DC.
If this server is Freeteam (and it probably is) then this server has been used for various left-wing activism collectives, and got confiscated by Dutch police various times throughout the years. For example, a death threat to Geert Wilders by some troll (server didn't log, as it intentionally never logged). The data was encrypted at rest, but you know how that goes. Everyone and their mother had shell access to Freeteam. (I'm someone's mother.)
A/I volunteers shutdown all their servers themselves because running an org which is sanctioned by USA as a terrorist organization isn't doable. This was one of the few servers which wasn't yet dissolved.