Rated 5 out of 5 stars

yazan: R. Menessec tarih: Ağu. 15, 2013 ·

Incredibly useful. Can't believe this isn't part of Stylish already.

Is there a way to limit the number of backups kept, besides turning them off entirely?

This review is for a previous version of the add-on (0.1.6.1-signed.1-signed). 

yazan: Herrminator (Geliştirici) tarih: Ağu. 15, 2013 ·

If you're familiar with 'about:config', you can go there and set the preference 'extensions.stylishsync.bakage'. The default is 14 (days).