Work Great Rated 4 out of 5 stars

Does exactly what is says clears your file cache and only that.
Checked forms and passwords still there, wish he added some form of info that it has finished or is running as it just sort of stalls Firefox while it runs the command as if you did it within options, so you can not use the browser while it runs, and have to guess if it finished.

This review is for a previous version of the add-on (1.0.1-signed.1-signed). 

Have you execute to clear file cache by using standard feature Firefox?
It is no prompt and finished in a second.
So I think not required to support prompt and progress bar.