We deliberately chose a design that could be implemented with a very small team. In fact there has never been more than about one person working full time on rr

We deliberately chose a design that could be implemented with a very small team. In fact there has never been more than about one person working full time on rr, usually less. That's one reason we bet on not using code instrumentation, for example. But yes, Mozilla deserves major credit for supporting us building this crazy thing --- and of course, releasing it.