Inside the Gulag is a five-and-a-half minute featurette on the Region 2 version of the Muppets Most Wanted Blu-ray.
Hosted by The Newsman, the featurette includes interviews with Kermit the Frog (identified as Constantine), Prison King, Big Papa, Danny Trejo, and Nadya (via phone).
Some alternate shots of Gulag 38B prisoners are shown in their cells, as well as on-set B-roll footage. The Muppets' official YouTube channel uploaded the whole feature on August 29, 2014. (YouTube)