Are we counting open source contributors or paid developers here?

Because I think there's a difference in assumption vs reality here. External contributors work in their free time and are, as I'm trying to point out in my other comment, unsustainable as a work model [1] [2]

[1] https://hg.mozilla.org/mozilla-central/graph/06b1ac14775250a...

[2] https://github.com/mozilla/gecko-dev/graphs/contributors