I use Firefox Containers to limit and logged in FB activity to that & never log in using FB other than FB website itself. I have no FB apps (including WhatsApp)

I use Firefox Containers to limit and logged in FB activity to that & never log in using FB other than FB website itself. I have no FB apps (including WhatsApp). I've been running uMatrix for a few months. My firefox tracking-prevention (similar to EFF's one, but probably not as good) is always using maximum privacy settings. I still have a few sites appear... AND for websites I've never even visited (that I'm aware of, & I'm the only user of this machine) There seems to be some serious fingerprinting going on, more than simple cookies.