The default "license" in this case would probably be All Rights Reserved.
When you say no license is enforced in your quote, general copyright laws would likely apply. I haven't looked into JSFiddle, but here's something in the Github Help Center:
You're under no obligation to choose a license. It's your right not to include one with your code or project, but please be aware of the implications. Generally speaking, the absence of a license means that the default copyright laws apply. This means that you retain all rights to your source code and that nobody else may reproduce, distribute, or create derivative works from your work. This might not be what you intend.
Even if this is what you intend, if you publish your source code in a public repository on GitHub, you have accepted the Terms of Service which do allow other GitHub users some rights. Specifically, you allow others to view and fork your repository within the GitHub site.
Generally, additional rights are provided to the site to hold your code and repository, as well as basic user operations within the app.
jsFiddle are not responsible or liable for any loss or damage of any kind during the usage of provided code.
This is mostly a disclaimer of liability. JSFiddle is just trying to say that they will not act on behalf of you in relation to copyright claims or the like. They don't want to be held accountable for anything that arises.
The impression that I get is that you can have an All Rights Reserved repository on JSFiddle, while acknowledging that they will not be responsible for anything to do with copyright or licensing, nor will they act on anyone's behalf.
In response to your bounty message, I'm not sure how much authoritative you can get after your quote. That quote seems to be from the jsfiddle.net site itself.