Add-ons

Allows you to quickly switch to a different language (User Interface, Spell Checker Dictionary and Website content) in your Mozilla application.

(Sorry, no plans to port this add-on to Webextensions)
BBCodeXtra is an extension, compatible with Mozilla FireFox (up to 57) and Seamonkey, which adds to the context menu new commands to insert BBCode/Html/XHtml codes in an easy and fast way...