This has nothing to do with “eyes only,” but the weirdest classification I ever saw on a document was as follows.
By way of explanation, it’s common to share certain types of classified info with allied nations. Such documents are marked as “Rel: [country name]”, with “rel” meaning releasable to. So it is common to see markings like “Top Secret Rel: UK/Can”, meaning you can show this document to British and Canadian citizens who possess the equivalent of Top Secret security clearances.
The document in question was marked “Secret: Rel: USSR.”
It was the draft text of the START treaty then under negotiation with the Soviet Union. Since the Soviets obviously knew the contents of the treaty, it was okay to show them the document. It was just a very surprising marking to see on a document. The only reason it was classified was the Soviets had requested that it remain secret until signature.
I was sorely tempted to steal the cover sheet as a souvenir. I didn’t because I thought I might get into trouble--cover sheets aren’t sensitive in and of themselves, but you are instructed to be very careful of them because you don’t want them being applied to the wrong documents. In retrospect, I really wish I had taken it.