I've been through all of Firefox `about:config` a few times in the past, fixing preferences to, e.g., try to disable umpteen different services that leak info or create potential vulnerabilities gratuitously, but this is the first I recall hearing of Normandy.
Apparently I missed `app.normandy.enabled`, because I think I would've remembered a name with connotations of a bloody massive surprise attack.
Incidentally, `app.normandy.enabled` defaults to `true` in the `firefox-esr` Debian Stable package. Which seems wrong for an ESR.
For personal use (not development), I run 3 browsers (for features/configurations and an extra bit of compartmentalization): Tor Browser for most things, Firefox ESR with privacy tweaks for the small number of things that require login, and Chromium without much privacy tweaks for the rare occasion that a crucial site refuses to work with my TB or FF setup.
Today's crucial cert administration oops, plus learning of yet another very questionable remote capability/vector, plus the questionable preferences-changing being enabled even for ESR... is making me even less comfortable with the Web browser standards "big moat" barrier to entry situation.
I know Mozilla has some very forthright people, but I'd really like to see a conspicuous and pervasive focus on privacy&security, throughout the organization, which, at this point, would shake up a lot of things. Then, with the high ground established unambiguously, I'd like to see actively reversing some of the past surveillance&brochure tendencies in some standards. And also see some more creative approaches to what a browser can be, despite a hostile and exploitive environment. Or maybe Brave turns out to be a better vehicle for that, but I still want to believe in Mozilla.