Comment by Certhas

So one of several teams working on Chrome Mobile (so not the rendering engine, JavaScript engine, etc...) was 40+ people. That tells us nothing about the size of the overall Chrome team.

I have seen comments on HackerNews that estimated 1000-4000 people working on Chrome at Google, but without a sound basis. Chromium had ~800 individuals author a commit, that's probably as close as we can get to actual hard facts.

The Platform Division which includes Chrome was 20.000+ but it's pure guesswork to break out numbers for Chrome for that.

Honestly my prior is that the vast majority of software dev work at Moz goes towards Firefox, I don't see any evidence to the contrary, including in terms of products released/developed. A modern browser is an enormously complex engineering feat, nothing else Moz releases is in that ballpark.

I guess bottom line is that we don't really know the exact breakdown.