Rated 4 out of 5 stars

per edz1 el set. 6, 2015 ·

only 4 stars as theres no option to show the seconds.

Will that be an update soon?

This review is for a previous version of the add-on (0.4.2.1-signed). 

per catweazle1 (desenvolupador) a set. 6, 2015 ·

sorry no update, when you want seconds in the Display i suggest you use Simple Timer.
https://addons.mozilla.org/de/firefox/addon/simple-timer/?src=search