Russia’s cutting-edge stealth fighter, the Su-57 Felon, has made headlines again. For the first time, Russia has signed a contract to export the fifth-generation aircraft, but the buyer’s identity is being kept secret, sparking a wave of speculation and intrigue.

The news broke on November 13 when Alexander Mikheev, head of Rosoboronexport, Russia’s state arms exporter, revealed the contract in an interview with Russian TV channel "Russia-1." Mikheev didn’t spill the beans on who the buy...