I'm curious if anyone can locate information on how much of that was spent specifically on Firefox, the browser. It seems like Mozilla was working on a bunch of peripheral stuff during that 2016-2017 period.
* Work on Firefox OS was still ongoing through 1H 2016. (https://groups.google.com/forum/#!msg/mozilla.dev.fxos/FoAwi...)
* They were building a free subscription service to check HIBP for your info. (https://monitor.firefox.com/)
* They were building a file-sharing service (https://github.com/mozilla/send/blob/master/CHANGELOG.md)
* They were building a new VR-first browser and content aggregator (https://blog.mozilla.org/blog/2018/09/18/firefox-reality-now...)