time.deltaTime rendering time of the engine or the headset?

Is time.deltaTime the rendering time of the last frame on the HMD or is it just the engine itself if those two times are different.

 

It's neither. It's the total time since the last frame.

 

"The time in seconds it took to complete the last frame" doesn't that mean the time it took the engine to render the last frame?

https://docs.unity3d.com/ScriptReference/Time-deltaTime.html

 

No, it doesn't. It means the total time since the previous frame. If you added up Time.deltaTime for every frame, it should equal Time.time.