B2G has always been “sandboxed” to some extent; every app/tab gets its own content process, which uses the Android security model: a separate uid per process, no group memberships, and kernel patches that require group membership for things like network access. But privilege escalation via kernel vulnerabilities is relatively common, so we also use the seccomp-bpf system call filter to reduce the attack surface that a compromised content process can directly access.
== Older ==
* [https://docs.google.com/a/mozilla.com/document/d/1qS4Q1goehqy-55hIQEsEA_XY3lF4xfFColNKQm37KSg/edit?usp=sharing Old Meeting Notes]