[Inkscape-user] What does "sodipodi" in svg file?

Hi,

I draw something in Inkscape and save in the svg file. But I don't understand what "sodipodi" means? I couldn't find it in the SVG manual http://www.w3.org/TR/2003/REC-SVG11-20030114/paths.html.

Would you please help me if you know what it means?

Thanks, Peng

<path sodipodi:type="arc" style="fill:blue;fill-opacity:1;stroke:black;stroke-width:1;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1" id="path8876" sodipodi:cx="246.42857" sodipodi:cy="707.36218" sodipodi:rx="152.14285" sodipodi:ry="82.14286" d="M 245.23643,789.50252 A 152.14285,82.14286 0 1 1 381.47519,669.53075 L 246.42857,707.36218 z" sodipodi:start="1.5786321" sodipodi:end="5.8045632" />