When the archives opened up and we were able to see the Soviet side of the story for the first time, were there great amounts of German papers they captured during the last days of the war that were finally released ?
Not immediately. German captured documents are stored in fond 500 of the Central Archives of the Ministry of Defense of the Russian Federation (TsAMO RF), and were not treated in any special way compared to the other archive documents. Order #181 of the Minister of Defense given on May 8th 2007 "On the declassification of archive documents of the Red Army and Navy for the period of the Great Patriotic War of 1941-1945" removed the secrecy from TsAMO files, which included all the German documents as well.
A project carried out jointly by Germany and Russia since 2011 has been scanning and publishing these archives online. The website is available in Russian and in German. Recently documents captured from Germany in WWI (dating 1910-1919) have been added to the archive as well.