Your own link says only the judge saw them, nobody else, and they won't be seen by anybody else until the case is over & nothing can be done to them. Never mind the info provided sounds like it's not terribly useful.

Actually, the judge opened the sealed cover, perused the contents thoroughly, then asked WMF counsel "How can these addresses be verified?" to which the reply was "These are all we have, and the website does not conduct verification of its users". The ANI counsel assisted his opponent by saying that service on the editors (D2-D4) is complete, they have not appeared, so can we please move on to my defamation takedowns. The judge then resealed the covers. So it can be safely inferred that WMF did not give ANI anything, and ANI never wanted the D2-D4 details at all, it was only a procedural formality so ANI can take on the "Wikimedia method/model" directly which is troubling all their SPAs/IPs. On a procedural note, once the case is complete and judgment given, the sealed covers are opened and anyone can inspect its contents. So nothing to fret over. Storm in a teacup.

As a European, I wonder if I can be protected via EU law?

If the foundation decides to share the details of the involved editors, a large group of contributors could quit their accounts and ask for removal of their contributions.

Considering the structure of Wikimedia, this will be a near impossible task, it may bring them to European courts next for violating EU law???

Wikipedia kowtows to every fascist government that asks them to. Remember when they banned users who called the Holodomer a genocide against the Ukranians by the Russians?