It adds two options:
Accuracy(x) - ensures the polyline will be within x units from the ideal arc/curve
ImproveAccuracyOnly - do not use the given accuracy 'x', if it would result in a worse curve than with the previous (2.8.0) implementation for a particular arc/curve.
As an added bonus there was a small bug in the existing implementation whereby the primitives were line strips but the vertices generated were actually suitable for GL_LINES, so the improved accuracy doesn't even have to come at a performance cost :-)"