Whatever happened to Secret Savin?
That's probably what the Federal employee that released it said.
Of course, since were dealing with those in the Federal government, the document probably was mislabeled and said, "For immediate Internet distribution."
From page 1 of the report:
The IAEA classification of the enclosed declaration is Highly Confidential Safeguards Sensitive; however, the United States regards this information as Sensitive but Unclassified.