Why do you need an add-on for facebook or google containers? Don't you just open a container, login to facebook, open a different container, log into google, and don't log into either in any other container?

Last time I checked, the site-specific container extensions (Facebook and Google) had a "don't open anything except the target site in the container" feature that appeared to be missing from the multi-account containers extension.

I agree that the best solution would be to add that functionality to the base extension rather than create a specific extension for every site people might want to block.

My understanding is they kick in automatically. So even if you're on someblog.com, the FB 'Like' buttons won't be tracking your behavior, nor will Google analytics and Google Doubleclick.

You don't need to have separate "site specific container" to do this. You can use Multi Account Containers[0] to configure any sites.

[0]: https://addons.mozilla.org/en-US/firefox/addon/multi-account...

It's not quite the same functionality. If you open Google in a regular container and then click a link that goes to a different site, it will load the new site in the same container. The Google container would open the new site in a different container.

Is there a chrome equivalent to this?

No, Chrome doesn't have equivalent APIs to those Firefox offers here.

The irony. You are asking if there is an extension that blocks the browsers company from tracking you. I don’t think they would allow it on their web store.

Chromium extension then please.