It seems this version by Ark may have been a copy, in their description they point to the "original", https://chrome.google.com/webstore/detail/jsonview/chklaanhf..., which directs to the version claimed to have a security vulnerability and appears to have been pulled.
I attempted to load something and realized the extension I had just previously been using stopped working. [screenshot of the disabled extension](http://imgur.com/jBmnwf4)
At one point I used and loved Vimperator and then migrated to Pentadactyl, but ultimately got fed up with Firefox's bloat and memory management issues.
I'd recommend checking out Firefox Aurora (http://www.mozilla.org/en-US/firefox/aurora/) - Firefox is really looking great these day. The new native developer tools are coming along nicely and hopefully will prove more stable than Firebug.
There's an Arch Linux dev that maintains a custom repo with Aurora builds and matching Aurora Pentadactyl packages in the AUR, for those on the distro.
source: https://github.com/callumlocke/json-formatter extension: https://chrome.google.com/webstore/detail/json-formatter/bcj...