This is a Firefox extension that makes the New Tab page into something useful instead of just a blank page.
This is just my hacked about version of the New Tab Jumpstart extension by Mihailo Lalevic, and unless you really know what you're doing, you probably want to use that instead! See also project page for that project.
Note that from Firefox 13.0 onwards Mozilla have implemented their own crappy 'new tab' thing. You have to override it to point to this instead, by changing browser.newtab.url in about:config to point to chrome://jumpstart/content/tabView.xul