feat(firefox): add the desktop Firefox browser module (task 0032)

Add Firefox as a single-purpose desktop Module configured entirely through home-manager's programs.firefox, and fan it out from the desktop aggregator so any Host with the desktop enabled brings the browser up. Ship stock mainline Firefox, hardened and de-monetized through locked enterprise policies (telemetry, studies, Pocket, offer-to-save-logins, the default-browser check, Firefox accounts and sync, and the sponsored new-tab surfaces all off). Force-install three extensions by policy, keyed by their verified add-on ids: uBlock Origin, Proton Pass, and SponsorBlock. Default search to DuckDuckGo over a lean list: the general-purpose commercial engines are hidden with metaData.hidden so Firefox does not reconcile them back in, leaving DuckDuckGo and Wikipedia. Theme the browser Nord from the shared Stylix scheme against the one profile, and register it as the default handler for the web-link schemes and HTML. Record the stock-Firefox-plus-policy-extensions decision as ADR 0005.
2026-07-23 23:04:19 -04:00
parent 039802b9e2
commit ee672d2479
5 changed files with 312 additions and 0 deletions
--- a/modules/desktop/firefox.nix
+++ b/modules/desktop/firefox.nix
@@ -0,0 +1,95 @@
+{ config, lib, ... }:
+# Firefox as the desktop browser: stock mainline, hardened and de-monetized by policy.
+let
+  cfg = config.modules.desktop.firefox;
+  user = config.user.name;
+
+  # A force-installed extension, keyed at the call site by the add-on's own id.
+  # Firefox fetches the signed add-on from Mozilla's site and enables it automatically.
+  forceInstalled = slug: {
+    install_url = "https://addons.mozilla.org/firefox/downloads/latest/${slug}/latest.xpi";
+    installation_mode = "force_installed";
+  };
+in
+{
+  options.modules.desktop.firefox.enable = lib.mkEnableOption "Firefox as the desktop browser";
+
+  config = lib.mkIf cfg.enable {
+    home-manager.users.${user} = {
+      programs.firefox = {
+        enable = true;
+
+        # Enterprise policies: enforced and unchangeable from the browser UI.
+        policies = {
+          DisableTelemetry = true;
+          DisableFirefoxStudies = true;
+          DisablePocket = true;
+          OfferToSaveLogins = false;
+          DontCheckDefaultBrowser = true;
+          DisableFirefoxAccounts = true;
+
+          # Strip the monetized surfaces from the new-tab page.
+          FirefoxHome = {
+            SponsoredTopSites = false;
+            SponsoredPocket = false;
+            Snippets = false;
+          };
+
+          # An ad and content blocker, the operator's password manager, and a
+          # video sponsor-skipper. All three are self-contained web extensions.
+          ExtensionSettings = {
+            "uBlock0@raymondhill.net" = forceInstalled "ublock-origin";
+            "78272b6fa58f4a1abaac99321d503a20@proton.me" = forceInstalled "proton-pass";
+            "sponsorBlocker@ajay.app" = forceInstalled "sponsorblock";
+          };
+        };
+
+        profiles.default = {
+          isDefault = true;
+
+          settings = {
+            # Sponsored surfaces the policies above do not reach.
+            "browser.urlbar.suggest.quicksuggest.sponsored" = false;
+            "browser.newtabpage.activity-stream.showSponsored" = false;
+            "browser.newtabpage.activity-stream.showSponsoredTopSites" = false;
+          };
+
+          search = {
+            # Declaring search overwrites Firefox's own engine list wholesale,
+            # so engines added later in the UI do not survive a rebuild.
+            force = true;
+            default = "ddg";
+
+            # The general-purpose commercial engines, hidden to leave a lean
+            # DuckDuckGo-and-Wikipedia list. They stay reachable through bangs.
+            # An engine carrying only metaData is treated as a builtin.
+            engines = {
+              google.metaData.hidden = true;
+              bing.metaData.hidden = true;
+              ebay.metaData.hidden = true;
+              "amazondotcom-us".metaData.hidden = true;
+            };
+            order = [ "ddg" ];
+          };
+        };
+      };
+
+      # Nord chrome from the shared Stylix scheme, against the one profile.
+      stylix.targets.firefox = {
+        enable = true;
+        profileNames = [ "default" ];
+      };
+
+      # Links opened from other applications land in Firefox.
+      xdg.mimeApps = {
+        enable = true;
+        defaultApplications = {
+          "text/html" = "firefox.desktop";
+          "application/xhtml+xml" = "firefox.desktop";
+          "x-scheme-handler/http" = "firefox.desktop";
+          "x-scheme-handler/https" = "firefox.desktop";
+        };
+      };
+    };
+  };
+}