[Alberta's Child]

That can’t be the reason to hide the information. The evidence was obtained by intercepting calls to and from the Russian guy’s phone. That’s been publicly known for more than two years, so it sure isn’t a secret.

More likely, the DOJ doesn’t want to have this remarkable precedent established where evidence obtained through covert surveillance of a foreign diplomat is formally recognized in a public U.S. court proceeding.

[DesertRhino]

Interesting take in the reason they want to keep it hidden.