diff --git a/hosts/tartarus/configuration.nix b/hosts/tartarus/configuration.nix
index 91a336b..5db369e 100644
--- a/hosts/tartarus/configuration.nix
+++ b/hosts/tartarus/configuration.nix
@@ -91,7 +91,34 @@
   };
 
   # Install firefox.
-  programs.firefox.enable = true;
+  programs.firefox = {
+    enable = true;
+    languagePacks = [ "ja" "en-US" ];
+
+    # profiles.osbm = {
+
+
+    # Check about:policies#documentation for options.
+    policies = {
+      DisableTelemetry = true;
+      DisableFirefoxStudies = true;
+      EnableTrackingProtection = {
+        Value= true;
+        Locked = true;
+        Cryptomining = true;
+        Fingerprinting = true;
+      };
+      # DisablePocket = true;
+      DisableFirefoxAccounts = true;
+      DisableAccounts = true;
+      DisableFirefoxScreenshots = true;
+      # OverrideFirstRunPage = "";
+      # OverridePostUpdatePage = "";
+      # DontCheckDefaultBrowser = true;
+      # DisplayBookmarksToolbar = "never"; # alternatives: "always" or "newtab"
+      # DisplayMenuBar = "default-off"; # alternatives: "always", "never" or "default-on"
+      # SearchBar = "unified"; # alternat
+  }
 
   programs.steam = {
     enable = true;