It means there were things that the prosecution did that were coordinated by evil parties way above Flynn's prosecutors, that were parts of other investigations (treason, sedition, etc.), that could not be revealed because those investigations were still ongoing
What's that mean in non lawyers speak?
It means there were things that the prosecution did that were coordinated by evil parties way above Flynn's prosecutors, that were parts of other investigations (treason, sedition, etc.), that could not be revealed because those investigations were still ongoing