ICONS:

The KiCad artwork for the 16px icons was made by Inigo Zuluaga for KiCad.

The work for the 26px icons and the 48px was done by Fabrizio Tappero, fabrizio.tappero<at>gmail.com

License: GPL or equivalent

Some of these icons are derived from icons available from various sources:

http://openiconlibrary.sourceforge.net/
http://www.iconfinder.com
Primo Icon Set by Webdesigner Depot, http://www.webdesignerdepot.com
http://www.oxygen-icons.org/
http://www.webdesignerdepot.com
http://www.everaldo.com/
http://schollidesign.deviantart.com/
GEDA project, http://www.gpleda.org/index.html
Tomaz Solc, http://www2.eng.cam.ac.uk/~pcjc2/geda/icons/mime/
http://www.tablix.org/~avian/blog/archives/2007/04/tango_icons_for_geda/
http://www.icons-land.com/
Inksacep icons, http://wiki.inkscape.org/wiki/index.php/TangoifiedIcons
http://sourceforge.net/apps/mediawiki/free-cad/index.php?title=Artwork#Icons
The Gnome artwork, http://art.gnome.org/
Tago Icon Library, http://tango.freedesktop.org/Tango_Icon_Library
http://www.cliparts101.com
Thorsten Behrens, http://lists.freedesktop.org/archives/libreoffice/2011-February/007210.html
Konstantin, http://electronix.ru/forum/index.php?showtopic=106246&view=findpost&p=1160223