How do the various tweens work?

Question

C++ / C#

I have always used DOTween and never thought about how it works inside.
While I was sitting, I came to such an elementary implementation:

While trying to understand how it works, a number of questions appeared:
1) I correctly assumed that the twin extension methods launch the coroutine on the GameObject, which the method receives as an argument?
2) How is movement done in the coroutine? Through a similar loop, or is linear interpolation used (Lerp, etc.)?
3) I noticed that there is a certain error at the end point of the movement (by about 0.0031), despite the fact that I force the position after the loop.
4) I noticed that the object moves a little longer than the time passed to the arguments. It seems to me, or is it really not worth relying on time in yunk?
I would be happy to hear any of your thoughts and thoughts on this topic!