@zvava wait theres actually a hidden pref that overrides this 'toolkit.telemetry.coverage.opt-out: true' you can use on prerelease im not sure exactly how much it does but it is in arkenfox user.js. i dont think prerelease telemetry is as big of a deal but i still would feel icky using a release that has a telemetry preference locked on even if theres some other thing that supposedly overrides that.,