Firefox profiles: Private, focused spaces for all the ways you browse

Hasn't this existed for many years?

I used to use Firefox profiles to separate work and personal over 10 years ago, nowadays I just use a different browser.

I tested this feature maybe 6 months ago. Have they copied the behavior of Chrome, where when you have multiple profiles open at once, it will open a link (say from Slack) in the most recently focused profile and window?

Last I checked, it didn’t, and it was quite annoying, coming from Chrome.