nix/nixos/common/software/gui/firefox.nix

{ ... }: {
  programs.firefox = {
    enable = true;
    # https://search.nixos.org/options?channel=23.05&show=programs.firefox.preferences&from=0&size=50&sort=relevance&type=packages&query=firefox
    preferences = {

      # Browser Settings
      "extensions.pocket.enabled" = false;
      "browser.newtabpage.activity-stream.feeds.telemetry" = false;
      "browser.newtabpage.activity-stream.telemetry" = false;
      "browser.ping-centre.telemetry" = false;
      "browser.startup.homepage" = "https://dir.sysctl.io";
      "browser.search.region" = "US";
      "browser.search.isUS" = true;
      "browser.bookmarks.showMobileBookmarks" = false;
      "browser.newtabpage.enabled" = false;
      "browser.tabs.firefox-view" = false;

      # Telemetry
      "toolkit.telemetry.server" = "null";
      "toolkit.telemetry.enabled" = false;
      "toolkit.telemetry.bhrPing.enabled" = false;
      "toolkit.telemetry.pioneer-new-studies-availble" = false;
      "toolkit.telemetry.firstShutdownPing.enabled" = false;
      "toolkit.telemetry.hybridContent.enabled" = false;
      "toolkit.telemetry.newProfilePing.enabled" = false;
      "toolkit.telemetry.shutdownPingSender.enabled" = false;
      "toolkit.telemetry.updatePing.enabled" = false;
      "toolkit.telemetry.reportingpolicy.firstRun" = false;
      "toolkit.telemetry.unified" = false;
      "toolkit.telemetry.archive.enabled" = false;

      # Data Reporting
      "datareporting.policy.dataSubmissionEnabled" = false;
      "datareporting.sessions.current.clean" = "true";
      "datareporting.healthreport.uploadEnabled" = false;
      "datareporting.healthreport.infoURL" = "null";

      # Other
      "devtools.onboarding.telemetry.logged" = false;
      "services.sync.prefs.sync.browser.newtabpage.enabled" = false;
      "general.useragent.locale" = "en-US";
      "distribution.searchplugins.defaultLocale" = "en-US";
    };
  };
}