Here is a description from the "Facebook Container" extension itself:
Facebook Container Extension FAQs wrote:How does it work?
Installing this extension closes your Facebook tabs, deletes your Facebook cookies, and logs you out of Facebook.
The next time you navigate to Facebook it will load in a new blue colored browser tab (the “Container”).
You can log in and use Facebook normally when in the Facebook Container. If you click on a non-Facebook link or navigate to a non-Facebook website in the URL bar, these pages will load outside of the container.
Clicking Facebook Share buttons on other browser tabs will load them within the Facebook Container. You should know that using these buttons passes information to Facebook about the website that you shared from.
Which website features will not function?
Because you will be logged into Facebook only in the Container, embedded Facebook comments and Like buttons in tabs outside the Facebook Container will not work. This prevents Facebook from associating information about your activity on websites outside of Facebook to your Facebook identity.
In addition, websites that allow you to create an account or log in using your Facebook credentials will generally not work properly. Because this extension is designed to separate Facebook use from use of other websites, this behavior is expected.
What does Facebook Container NOT protect against?
It is important to know that this extension doesn’t prevent Facebook from mishandling the data that it already has, or permitted others to obtain, about you. Facebook still will have access to everything that you do while you are on facebook.com, including your Facebook comments, photo uploads, likes, any data you share with Facebook connected apps, etc.
Rather than stop using a service you find valuable, we think you should have tools to limit what data others can obtain. This extension focuses on limiting Facebook tracking, but other ad networks may try to correlate your Facebook activities with your regular browsing. In addition to this extension, you can change your Facebook settings, use Private Browsing, enable Tracking Protection, block third-party cookies, and/or use Firefox Multi-Account Containers extension to further limit tracking.
What data does Mozilla receive from this extension?
Mozilla does not collect data from your use of the Facebook Container extension. We do receive the number of times the extension is installed or removed.
"Worldwide Radio" is another extension you can use to listen to radio stations around the globe while browsing. There is also the "Dark Reader" extension for reading while in the dark at night time so it's not too bright on your eyes. I am sort of a technology junkie, but these browsers are really cool. Hope somebody here on PoFo finds them useful!
"All in all the time." -US Navy SEAL saying
"Put everything you’ve got in what you do. If you do that, win or lose, you will be a champion." -PO