A Russian-linked group of hackers, who recently attacked government websites, stole documents, among which were those that related to Ukraine. This is reported with reference to its own sources by the German Der Spiegel.
Russia's War Against Ukraine
Ukraine-European Union Relations
112.ua: Hackers stole documents on EU-Ukraine talks from German websites
German Der Spiegel reports a Russian-linked group of hackers stole documents, related to Ukraine.