firefox: declaratively define important settings & extensions

Closes #4

home/qenya/default.nix

@@ -2,6 +2,7 @@
   imports = [
     ./dconf
     ./cli.nix
+    ./firefox.nix
     ./git.nix
     ./tmux.nix
     ./vscode.nix

home/qenya/firefox.nix

@@ -0,0 +1,51 @@
+{ config, lib, pkgs, ... }:
+
+{
+  programs.firefox = {
+    # coming in 24.11
+    # languagePacks = [ "en-GB" ];
+
+    profiles.default = {
+      extensions = with pkgs.nur.repos.rycee.firefox-addons; [
+        bitwarden
+        ublock-origin
+      ];
+
+      settings = {
+        "browser.startup.page" = 3; # resume previous session
+        "browser.newtabpage.activity-stream.showSponsored" = false;
+        "browser.newtabpage.activity-stream.showSponsoredTopSites" = false;
+
+        # disable telemetry
+        "datareporting.healthreport.uploadEnabled" = false;
+        "app.shield.optoutstudies.enabled" = false;
+        "browser.crashReports.unsubmittedCheck.autoSubmit2" = false;
+
+        # disable prefetch?
+
+        # DNS over HTTPS
+        "network.trr.custom_uri" = "https://base.dns.mullvad.net/dns-query";
+        "network.trr.excluded-domains" = "detectportal.firefox.com";
+        "network.trr.mode" = 3;
+        "network.trr.uri" = "https://base.dns.mullvad.net/dns-query";
+
+        "browser.search.suggest.enabled" = false;
+        "browser.urlbar.suggest.searches" = false;
+
+        "dom.security.https_only_mode" = true;
+        "browser.contentblocking.category" = "strict"; # Enhanced Tracking Protection
+        # I think these are implied by the above
+        # "privacy.donottrackheader.enabled" = true;
+        # "privacy.trackingprotection.enabled" = true;
+        # "privacy.trackingprotection.emailtracking.enabled" = true;
+        # "privacy.trackingprotection.socialtracking.enabled" = true;
+
+        "privacy.sanitize.sanitizeOnShutdown" = true;
+        "privacy.clearOnShutdown_v2.historyFormDataAndDownloads" = false;
+
+        "dom.private-attribution.submission.enabled" = false; # disable "Privacy-Preserving Attribution for Advertising"
+        "extensions.autoDisableScopes" = 0; # automatically enable extensions installed through nix
+      };
+    };
+  };
+}

hosts/tohru/home.nix

@@ -4,7 +4,7 @@
   dconf.enable = true;
 
   programs = {
-    firefox.enable = true; # TODO: config is not yet nix-ified
+    firefox.enable = true;
     vscode.enable = true;
   };