> MemGC (Memory Garbage Collector) is a memory garbage collection system that seeks to defend the browser from UAF (Use-after-free) vulnerabilities by taking responsibility for freeing memory away from the programmer and instead automating it, only freeing memory when the automation has detected that there are no more references left pointing to a given block of memory.

Interesting; I don't think this has been announced before. It sounds similar in concept to Chrome's Oilpan (still not shipped AFAIK).