Firefox container options  

I need an explanation of what this about.

Attachment 211703

thanks

kitpzyxmsir said:

I need an explanation of what this about.

Mozilla have one for you...

Container tabs are like normal tabs except that the sites you visit will have access to a separate slice of the browser's storage. This means your site preferences, logged in sessions, and advertising tracking data won't carry over to the new container. Likewise, any browsing you do within the new container will not affect your logged in sessions, or tracking data of your other containers.

Multi-Account Containers | Firefox Help

ok, but I still don't understand what that has to do with that particular addon and why it requires container tabs.

I have since removed that extension, but now my FoxyTabs addon, which I also had at the time I was using Cookie Manager, has replaced Cookie Manager in the notification.