Yes this, we did some brainstorming and solicited user feedback about names and decided Containers makes sense for a general audience. Docker Containers and 'Contextual Idendities' are kind of inside baseball.
I kid, but it makes sense. Containers describes the implementation, not the user experience or benefit.
(Reusing the name "Persona" for any new project is a running joke at Mozilla. :)
This. Sure, "contextual identities" sounds too academic, but who knows, maybe Containers (as a word) will become as ubiquious as Tabs are today (very common word in German today): Hey, dude, open a container ;)