Did they use deepfake technology for that flashback scene? Spoilers.

In a flashback of laser-sword practice that sees young Luke and Leia sparring with each other, when Luke removes a mask he looks the same as in Empire. It didn't seem like a 3D rendering, it seemed as though a real young Luke's face was somehow fitted onto the face of the actor performing in that scene. Young Leia, on the other hand, looked weird, didn't know what was going on.