This is great! I remember Mozilla making an attempt at time-travel debugging in the browser, I wonder where this effort went.
It’s also great that they’re describing how their recorder works (here and here). As far as I understand, their approach is much less powerful than the one taken by RR (“Replay’s recorder only works in cooperation with the program being recorded: recordings made with an unmodified program that hasn’t been adapted to use the recorder will almost certainly fail to replay.”, while RR doesn’t need the debuggee’s cooperation), but their integration with interpreted language’s runtime is a serious advantage (although I think Pernosco, which is based on RR, has integration with JS engines).
These are ex-Mozillians. It’s the continuation.
That’s what I suspected, thanks for confirming :). Mozilla is the source of a ton of cool tech that came out in the 2010s (Pernosco, Rust, Coqui…). I wonder if we will see the same thing happen in the next decade, now that it has refocused on Firefox.