Just picked up from what the founder and editor of Motorbeam.com said in the comment section on his RC390 review. "They" is referring to KTM.
Search for the key word "twin" at: 2015 KTM RC 390 Test Ride Review | MotorBeam – Indian Car Bike News & ReviewsFaisal Khan Mod kp • 3 months ago. They are making two parallel-twin engines which will be made by Bajaj in India.