German MiG-29

In a book published last year, titled Dreamland: The Secret History of Area 51, Peter Merlin sheds light on US Air Force evaluation tests in Nevada in 1991-1992 of one MiG-29 formerly operated by East Germany prior to German reunification under codename Have Loan. The MiG-29 evaluated at the Tonopah Test Range by the Air Force was given the cover designation YF-116A for security reasons (the US Air Force chose to revive the pre-1962 F-for-Fighter designation sequence and assign cover designations in that sequence to captured and/or defected MiGs to prevent the USSR from learning about evaluation tests of those MiG jet fighters in Nevada in the 1970s and 1980s, although YF-1xx designations would also be given to top-secret US-built aircraft, including the F-117 Nighthawk, Bird of Prey, and Tacit Blue).

https://www.designation-systems.net/usmilav/coverdesignations.html