Thanks for the heads-up! Yeah, I'm running ESR 128 right now so when I upgrade to the next ESR I'll keep an eye on these settings.

You can preload them now in your profile `user.js` - FF will ignore any settings it does not know about, it's "safe" to leave old things that got deleted and add new things coming in the next ESR without harm (that I'm aware, been doing it for years). A user.js is portable, not relying on any given vendor configurations.