About half-way down: https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/internals/preferences.html https://firefox-source-docs.mozilla.org/too

About half-way down: https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/internals/preferences.html https://firefox-source-docs.mozilla.org/toolkit/components/t... toolkit.telemetry.enabled and toolkit.telemetry.unified have a complex relationship. about:preferences#privacy Uncheck all . toolkit.telemetry.unified = false toolkit.telemetry.enabled = false toolkit.telemetry.reportingpolicy.firstRun = false datareporting.policy.dataSubmissionEnabled = false datareporting.sessions.current.clean = true In a couple min of searching it looked unlikely that I'd find any current documentation about these flags, the bhrPing and hybridContent are probably remains, but were still present in my existing profiles. devtools.onboarding.telemetry.logged = false browser.newtabpage.activity-stream.feeds.telemetry = false browser.newtabpage.activity-stream.telemetry = false browser.ping-centre.telemetry = false toolkit.telemetry.bhrPing.enabled = false toolkit.telemetry.hybridContent.enabled = false There are some additional prioping entries under the telemetry module which are associated with Nightly / dev builds.