Both are small addons and single purpose.
This one protects against IDN homograph attacks with a warning screen
You should set "network.IDN_show_punycode" in about:config to true, then you can see **real** address in the url bar.
CSS Exfil Protection... https://addons.mozilla.org/en-US/firefox/addon/css-exfil-protection/
This one shows if the page contains the attack with counter badge on the addon icon.