Comment by dblohm7
1 day ago
They've been available natively on Nightly with some basic UI support since they were first implemented a decade ago. Some other pre-release builds have them too but it's been too long and I cannot remember which ones did or didn't.
I don't use Nightly and I've been using containers for I think that long without any extension for it.
Edit: looks like I enabled them manually and couldn't remember/find it, it's in about:config under the name "privacy.userContext" instead of "containers".
as far as i remember, the low level container functionality was always in the core browser. what the extension adds is the UI to manage containers. with this change it appears the UI is merged back into the core browser.
It's been there just as long, turn it on with "privacy.userContext.ui.enabled" and manage them at "about:preferences#containers"
The addons added extra functionality but everything they've listed in this announcement is already there. Sounds like they're just flipping these two flags by default.