Rated 5 out of 5 stars

Firefox 20 Support is ready on the addon's website. And Steve (author) says it will be available here on Mozilla as soon as it has been reviewed by the Firefox team.
A very usefull addon for many usages, e.g. blogging, emails, webdeveloper and so on.

This review is for a previous version of the add-on (0.5.284).