Strips comments and !important declarations Rated 2 out of 5 stars

Firefile has lots of potential but I don't think it's currently a fully working solution. Especially if you want to edit the CSS file of a WordPress site.

The main issue with using it on a WordPress site is it's going to strip your stylesheet header and your theme isn't goiing to work after that.

For any site there is a good chance it's going to strip all your comments.

Another thing it's going to do which can really mess with your stylesheet is strip all your !important declarations.

So use with care!

This review is for a previous version of the add-on (0.8.4). 

You can set an option to make FireFile keep css comments.
The !important issue is fixed in version 0.8.6 (