[ excerpt from developer's web site ]

Nuvola SVG evolution of SKY icon theme.

NUVOLA is an SVG based icon theme.  This mean that all icons where
designed with a vector graphics software and then exported to SVG.
Icons of the KDE version of Nuvola are PNG images (unscalable).
SVG files are available (not always updated) on my web site in the
"svg" section.

WWW: http://www.kde-look.org/content/show.php?content=5358
WWW: http://www.icon-king.com/