This is an icon theme that follows the Tango visual guidelines. Currently it depends on Imagemagick for creation of 24x24 bitmaps by adding a 1px padding around the 22x22px version. For GNOME and KDE you will also need icon-naming-utils that allow the theme to work in these environments before they follow the new naming scheme.
There's a Wikipedia article. Also Wikimedia Commons has a page about the icons that includes more icons than the ones available in this repository. The [Gnome desktop icons] are also similar but contains more and partially different icons than Tango.
