Yes, Chromium is basically entirely memory unsafe modulo mitigations [1], with the exception of some codecs being generated from a memory safe language. I meant that the memory safe parts of Firefox are a very small minority: it's also an enormous pile of memory unsafe C++.

1: There's a very clever project that'll protect against use after free that's being worked on right now: https://docs.google.com/document/d/1m0c63vXXLyGtIGBi9v6YFANu...

With that and memory tagging, the vast majority of vulnerabilities go from remote code execution to just denial of service.