Did you uninstall that after using it? Otherwise that extension still has the ability to "read and change your data on all facebook.com sites." For all you know, it may have uploaded a copy of all your Facebook data to its servers already.

I deactivate the extension after usage. I also looked at the console/source code and the only external urls the extension is calling are google services (Analytics and Chrome Store) I have analytics blocked in the HOSTS file anyway.