Tamper Data.
I think this extension wasn't posted yet (I seached kmext and the forum and didn't find it). I placed it under Tools -> Development Tools -> Tamper Data.
Honestly, it's pretty much useless, unless you are web developer
.
Languages included: de-DE, en-US, es-ES, fr-FR, it-IT, pl-PL, pt-BR, ru-RU, uk-UA.
More infos
here.