In the current world line, the death of Peter III is considered a mysterious death, but one reporter says that in childhood, at their family home, in a nicely photo-illustrated travelogue series...
So it is said. Incidentally, in Inagi City where the author is from, there is also a U.S. military recreation facility called the Tama Service Facility, and officially it is supposed to be just a recreation facility where high-ranking U.S. military personnel enjoy horseback riding and golf, but the location is where an old Imperial Army ammunition depot used to be, and while it’s not clear whether this too was dug out by Koreans from the external territories for the sake of secrecy, the underground is dug very, very deep, and a subway called the Musashino Minami Line, which operates a U.S. military–only freight line, runs nearby, and there are basically almost no Inagi citizens who believe that place is a mere recreation facility.
This case is part of the Mandela Effect case database based on "The Window of Opportunity: A Guidepost to the Mandela Effect — The Ultra-Secret X-Files" by Aoyama Takuto.