On which anchor points is the SVG path ellipse calculated?

Question

SVG

SVG paths have a circle drawing property, I understand that the center of the circle is the last point used, but how is the final coordinate of the resulting arc calculated if it needs to be specified independently? Isn't it more logical to do the calculation through the measure of the angle? After all, if you specify an end point that does not lie on an arc, then the render still draws this arc and ends it approximately at that point. How does this algorithm work? I'm not angry if you give a link "to read" I think I'll master it, but still I would like to hear a chewed answer.