In his words:
Officially announced at JSConf EU 2011, but used for almost a year and half prior by the community, we are just going to offer this logo for use with JS projects. If you like it use it, if you don't that's cool too. Just don't complain unless you want to offer a different one, post your alternative to twitter with the tag #jslogo. We are releasing this under a WTFPL license so you can print it on anything, use it anywhere, and never have to worry about royalties, licenses, and other such things.Check it out, it is currently available in the file formats favicon, ASCII art, EPS, JPG, PDF, PNG, SVG.