* Supports Firefox 10.0+ and SeaMonkey 2.7+ but not Thunderbird. Also does not support the ViewAbout extension (about:config must be opened in a normal tab or window).
* The source comments themselves are included in the files packaged with your browser. These comments are written by the developers themselves, in English, and thus this extension is English only.
* Virtually no addons I checked bothered to have source descriptions for their default preferences. I might consider adding support for this in a future version, but it doesn't look like it's worth it at this point.
* The whole point of this extension is to simply and quickly access the information about the preferences that is already shipped with the Firefox releases. It is way outside the scope of this project to rewrite it to load up a massive, meticulously maintained, remotely updated, fully translated, database of every single preference for your browser and all extensions. This extension is not a complete substitute for looking up things online yourself. [http://kb.mozillazine.org/About:config_entries] So, please avoid reviews telling me that my extension really needs to be a different extension to be better. ;)