/x-axis-rotation/ is (I think) the orientation of the minor (shorter) axis of the ellipse, measured clockwise with East being 0 deg. Obviously for an arc which is a portion of a circle, the rotation has no effect.
/large-arc-flag/ and /sweep-flag/ work together. To understand them you have to appreciate that there are always two possible circles or ellipses on whose circumference the start and end points can fall:
- The circle where the shortest route from start to end is the anticlockwise one ('anticlockwise short')
- The circle where the shortest route from start to end is the clockwise one ('clockwise short')
/large-arc-flag/ determines whether the longer, or the shorter path between the start and end points is used.
/sweep-flag/ determines which direction (0=negative/anticlockwise, 1=positive/clockwise) we move in round the circle when going from start to end.
Basically the combination of /large-arc-flag/ and /sweep-flag/ chooses between one of the possible circles and the other, and dictates whether we use the larger or smaller way round that circle.
That's to say, the combination 0 0 uses the same circle as 1 1 (anticlockwise short), and 0 1 uses the same circle as 1 0 (clockwise short) - and 0 1 and 1 1 take the long way round the chosen circle.
(Good diagram of this here)
NB that it is a lot easier to use the circle element instead of trying to draw a complete circle with arcs.
