The fields:
browser.ml.enable browser.ml.chat.enabled browser.ml.chat.menu browser.ml.chat.page browser.ml.chat.page.footerBadge browser.ml.chat.page.menuBadge browser.ml.linkPreview.enabled browser.ml.pageAssist.enabled browser.tabs.groups.smart.enabled browser.tabs.groups.smart.userEnabled extensions.ml.enabled browser.search.visualSearch.featureGate
Most people have no idea their data is being scraped from the services they use either, that doesn’t mean they like it or that they should.
Unlike some folks in this thread, I never got an opt in pop up for the “features” on desktop or mobile.