Great extension we have there! That reader is very easy to use, but we have a huge customisation potential if we look into the settings. Especially with the Rules panel.

Just a suggestion : It would be nice if we had the ability to create our own themes (I mean, import and export our own CSS sheets).
Also, I think there should be an option to make the Feedbro icon "uncolorized". Most of the buttons in Firefox are in shades of grey by default, and the icon of the extension adds some visual "noise", making sometimes hard to see the number of updates with a fast glance :/