Rosenstein out at Justice defenitely makes the most sense for the [RR-out] reference, but there's another hypothisis.

[RR-out], referencing the "railroad out" Amtrak train derailment last month in Oregon in which theories were flying that Antifa had something to do with it.

nypost.com/2017/12/18/object-on-tracks-may-be-cause-of-deadly-amtrak-derailment/

thegatewaypundit.com/2017/11/every-officer-antifa-anarchists-sabotage-train-olympia-commune-raided-police/

Hell, Snopes even did a "fact check" on the incident.

snopes.com/antifa-pour-concrete-on-tracks-causing-an-amtrak-train-to-derail/

Just throwing it out there as an alternative theory.