FadedHearts

I think that cannot be done thorough a Firefox add-on because it’s something related to the web server. But there are add-ons that will let you know the data transfer between the site and your PC.

I think Avast should be added to the list. It’s one of the best anti virus guard that i have used. Since Avast was not on the list i voted for Kaspersky. It’s my second best choice