Just the fact that both Firefox and Chrome are version 100 as we speak is pretty suspect by itself, not that it really matters why they did it
So trying to shift development processes more toward continuous delivery (within reason, given desktop software) is meaningless, then? Come on.
Sure, do that. But by chance they are both on 100?
They each release on a regular schedule. I don’t think that they have the same schedule. You can see each of them incrementing with each release. They have been doing this for several years now. It really is just chance they they are at 100 in roughly the same time.