Any better explanation about Time.deltaTime????

From my understanding Time.deltaTime: renders based on the time it took to render the last frame.

1. From what I understand not all frames are rendered with the same speed even if the fps states 60 fps or 30 fps, right?
2. Therefore which frame is the last frame, and the value of delta.Time will change all the time. Example: the first frame is 0.016, meaning it will take 0.16 to render the next frame, and the next, and the next,....?
3. If the answer 2 is YES, can we conclude that the Time.deltaTime is the time it took to render the first frame?

please email the ansers to assouaalbert@gmail.com