The one I uploaded was done in Serif Affinity Designer because I'd used it a bit before.
It always adds at least one pixel to the viewport beyond the right and bottom of the image.
But maybe that wouldn't matter as long as the actual image was the correct size.
I'm still not sure why nanosvg wouldn't show the gradient fill.
I will try and test with the fill at right angles instead of skewed slightly at 100°.