In jsfiddle.net if one choose framework as jQuery or Mootools they will get an option for choosing jQuery ( edge ) and Mootools( edge ).
I googled it quite a bit but
It is the jQuery nightly build from github...
jQuery JavaScript Library v1.6.3pre Live From Git (b22c9046529852c7ce567df13397849e11e2b9cc)
Here is the link: link (jsfiddle uses this)
Here is the jQuery github link: github-link
An edge build usually refers to some kind of "nightly" or not yet released build. The cutting edge, basically the latest source packaged up.