They're not containers as in Linux containers, they're "contextual identities" within the same Firefox process, that isolate things like cookies. Much weaker is

They're not containers as in Linux containers, they're "contextual identities" within the same Firefox process, that isolate things like cookies. Much weaker isolation (technologically) than process/user privilege separation, but OTOH highly usable. (Well, there's the e10s process separation, but nothing anything extra for multi-account containers, as far as I understand). What things it isolates are listed here: https://wiki.mozilla.org/Security/Contextual_Identity_Project/Containers#Implementation_Details https://wiki.mozilla.org/Security/Contextual_Identity_Projec... FWIW they work great.