[WorldMaker]

> Any details, how do they leak?

Extensions, mostly. You have to be real careful which extensions you install because extensions run at the window level (mostly) rather than the container level and see across/through containers.

Also things like auto-fill (including password suggestions); if you like that being very specific to context, then you'd want different profiles rather than containers.

I've found I've been using a mixture of profiles and containers, myself, to balance ease of access (containers are fast to launch and can auto-launch per specific sites) versus better extension control and auto-fill/etc separation.

(ETA: As for finger-printing, both containers and profiles are equal on the most common finger-printing: cookies and localStorage. Neither protects you well from IP Address tracking, which is a growing concern, but not the approach of at least the big players like Google or Facebook, yet.)