diff --git a/app/assets/javascripts/discourse/tests/index.html b/app/assets/javascripts/discourse/tests/index.html
index 3582ff67394..c4fb561923e 100644
--- a/app/assets/javascripts/discourse/tests/index.html
+++ b/app/assets/javascripts/discourse/tests/index.html
@@ -54,9 +54,9 @@
     <script src="{{rootURL}}assets/discourse.js"></script>
 
     <script src="{{rootURL}}assets/locales/en.js" data-embroider-ignore></script>
-    <script src="{{rootURL}}extra-locales/0000000000000000000000000000000000000000/mf" data-embroider-ignore></script>
-    <script src="{{rootURL}}extra-locales/0000000000000000000000000000000000000000/admin" data-embroider-ignore></script>
-    <script src="{{rootURL}}extra-locales/0000000000000000000000000000000000000000/wizard" data-embroider-ignore></script>
+    <script src="{{rootURL}}extra-locales/0000000000000000000000000000000000000000/en/mf.js" data-embroider-ignore></script>
+    <script src="{{rootURL}}extra-locales/0000000000000000000000000000000000000000/en/admin.js" data-embroider-ignore></script>
+    <script src="{{rootURL}}extra-locales/0000000000000000000000000000000000000000/en/wizard.js" data-embroider-ignore></script>
     <script src="{{rootURL}}assets/test-site-settings.js" data-embroider-ignore></script>
     <script src="{{rootURL}}assets/admin.js" data-embroider-ignore></script>
 
diff --git a/app/controllers/extra_locales_controller.rb b/app/controllers/extra_locales_controller.rb
index d120fe3f3da..f42aca971fd 100644
--- a/app/controllers/extra_locales_controller.rb
+++ b/app/controllers/extra_locales_controller.rb
@@ -23,50 +23,54 @@ class ExtraLocalesController < ApplicationController
       @js_digests ||= { site_specific: {}, shared: {} }
     end
 
-    def bundle_js_hash(bundle)
-      bundle_key = "#{bundle}_#{I18n.locale}"
+    def bundle_js_hash(bundle, locale:)
+      bundle_key = "#{bundle}_#{locale}"
       if bundle.in?(SITE_SPECIFIC_BUNDLES)
         site = RailsMultisite::ConnectionManagement.current_db
 
         js_digests[:site_specific][site] ||= {}
         js_digests[:site_specific][site][bundle_key] ||= begin
-          js = bundle_js(bundle)
+          js = bundle_js(bundle, locale: locale)
           js.present? ? digest_for_content(js) : nil
         end
       elsif bundle.in?(SHARED_BUNDLES)
-        js_digests[:shared][bundle_key] ||= digest_for_content(bundle_js(bundle))
+        js_digests[:shared][bundle_key] ||= digest_for_content(bundle_js(bundle, locale: locale))
       else
         raise "Unknown bundle: #{bundle}"
       end
     end
 
-    def url(bundle)
+    def url(bundle, locale: I18n.locale)
+      hash = bundle_js_hash(bundle, locale:)
+
       base = "#{GlobalSetting.cdn_url}#{Discourse.base_path}"
-      path = "/extra-locales/#{bundle_js_hash(bundle)}/#{bundle}"
+      path = "/extra-locales/#{hash}/#{locale}/#{bundle}.js"
       query = SITE_SPECIFIC_BUNDLES.include?(bundle) ? "?__ws=#{Discourse.current_hostname}" : ""
       "#{base}#{path}#{query}"
     end
 
-    def client_overrides_exist?
-      bundle_js_hash(OVERRIDES_BUNDLE).present?
+    def client_overrides_exist?(locale: I18n.locale)
+      bundle_js_hash(OVERRIDES_BUNDLE, locale: locale).present?
     end
 
-    def bundle_js(bundle)
-      locale_str = I18n.locale.to_s
+    def bundle_js(bundle, locale:)
+      locale_str = locale.to_s
       bundle_str = "#{bundle}_js"
 
-      case bundle
-      when OVERRIDES_BUNDLE
-        JsLocaleHelper.output_client_overrides(locale_str)
-      when MF_BUNDLE
-        JsLocaleHelper.output_MF(locale_str)
-      else
-        JsLocaleHelper.output_extra_locales(bundle_str, locale_str)
+      I18n.with_locale(locale) do
+        case bundle
+        when OVERRIDES_BUNDLE
+          JsLocaleHelper.output_client_overrides(locale_str)
+        when MF_BUNDLE
+          JsLocaleHelper.output_MF(locale_str)
+        else
+          JsLocaleHelper.output_extra_locales(bundle_str, locale_str)
+        end
       end
     end
 
-    def bundle_js_with_hash(bundle)
-      js = bundle_js(bundle)
+    def bundle_js_with_hash(bundle, locale:)
+      js = bundle_js(bundle, locale: locale)
       [js, digest_for_content(js)]
     end
 
@@ -82,14 +86,17 @@ class ExtraLocalesController < ApplicationController
 
   def show
     bundle = params[:bundle]
-    raise Discourse::InvalidAccess.new if !valid_bundle?(bundle)
+    raise Discourse::NotFound if !valid_bundle?(bundle)
+
+    locale = params[:locale]
+    raise Discourse::NotFound if !I18n.available_locales.include?(locale.to_sym)
 
     digest = params[:digest]
     if digest.present?
       raise Discourse::InvalidParameters.new(:digest) unless digest.to_s.size == SHA1_HASH_LENGTH
     end
 
-    content, hash = ExtraLocalesController.bundle_js_with_hash(bundle)
+    content, hash = ExtraLocalesController.bundle_js_with_hash(bundle, locale:)
     immutable_for(1.year) if hash == digest
 
     render plain: content, content_type: "application/javascript"
diff --git a/config/routes.rb b/config/routes.rb
index a426697a5dd..82e03681297 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -460,7 +460,10 @@ Discourse::Application.routes.draw do
     get "email/unsubscribed" => "email#unsubscribed", :as => "email_unsubscribed"
     post "email/unsubscribe/:key" => "email#perform_unsubscribe", :as => "email_perform_unsubscribe"
 
-    get "extra-locales/:digest/:bundle" => "extra_locales#show"
+    get "extra-locales/:digest/:locale/:bundle" => "extra_locales#show",
+        :constraints => {
+          format: :js,
+        }
 
     resources :session, id: RouteFormat.username, only: %i[create destroy become] do
       get "become" if !Rails.env.production?
diff --git a/spec/requests/extra_locales_controller_spec.rb b/spec/requests/extra_locales_controller_spec.rb
index 4a531586130..e0e6c16ddfe 100644
--- a/spec/requests/extra_locales_controller_spec.rb
+++ b/spec/requests/extra_locales_controller_spec.rb
@@ -6,35 +6,35 @@ RSpec.describe ExtraLocalesController do
 
   describe "#show" do
     it "won't work with a weird parameter" do
-      get "/extra-locales/#{fake_digest}/-invalid..character!!"
+      get "/extra-locales/#{fake_digest}/en/-invalid..character!!.js"
       expect(response.status).to eq(404)
     end
 
     it "needs a valid bundle" do
-      get "/extra-locales/#{fake_digest}/made-up-bundle"
-      expect(response.status).to eq(403)
+      get "/extra-locales/#{fake_digest}/en/made-up-bundle.js"
+      expect(response.status).to eq(404)
     end
 
     it "requires a valid digest" do
-      get "/extra-locales/ZZZ/overrides"
+      get "/extra-locales/ZZZ/en/overrides.js"
       expect(response.status).to eq(400)
     end
 
     it "caches for 1 year if version is provided and it matches current hash" do
-      get "/extra-locales/#{ExtraLocalesController.bundle_js_hash("admin")}/admin"
+      get "/extra-locales/#{ExtraLocalesController.bundle_js_hash("admin", locale: :en)}/en/admin.js"
       expect(response.status).to eq(200)
       expect(response.headers["Cache-Control"]).to eq("max-age=31556952, public, immutable")
     end
 
     it "does not cache at all if version is invalid" do
-      get "/extra-locales/#{fake_digest}/admin"
+      get "/extra-locales/#{fake_digest}/en/admin.js"
       expect(response.status).to eq(200)
       expect(response.headers["Cache-Control"]).not_to include("max-age", "public", "immutable")
     end
 
     it "doesn’t generate the bundle twice" do
       described_class.expects(:bundle_js).returns("JS").once
-      get "/extra-locales/#{fake_digest}/admin"
+      get "/extra-locales/#{fake_digest}/en/admin.js"
     end
 
     context "with plugin" do
@@ -60,7 +60,7 @@ RSpec.describe ExtraLocalesController do
       after { JsLocaleHelper.clear_cache! }
 
       it "includes plugin translations" do
-        get "/extra-locales/#{fake_digest}/admin"
+        get "/extra-locales/#{fake_digest}/en/admin.js"
         expect(response.status).to eq(200)
         expect(response.body.include?("github_badges")).to eq(true)
       end
@@ -72,13 +72,13 @@ RSpec.describe ExtraLocalesController do
       it "works for anonymous users" do
         TranslationOverride.upsert!(I18n.locale, "js.some_key", "client-side translation")
 
-        get "/extra-locales/#{ExtraLocalesController.bundle_js_hash("overrides")}/overrides"
+        get "/extra-locales/#{ExtraLocalesController.bundle_js_hash("overrides", locale: :en)}/en/overrides.js"
         expect(response.status).to eq(200)
         expect(response.headers["Cache-Control"]).to eq("max-age=31556952, public, immutable")
       end
 
       it "returns nothing when there are not overridden translations" do
-        get "/extra-locales/#{fake_digest}/overrides"
+        get "/extra-locales/#{fake_digest}/en/overrides.js"
         expect(response.status).to eq(200)
         expect(response.body).to be_empty
       end
@@ -99,7 +99,7 @@ RSpec.describe ExtraLocalesController do
             "{NUM_RESULTS, plural, one {1 result} other {many} }",
           )
 
-          get "/extra-locales/#{fake_digest}/overrides"
+          get "/extra-locales/#{fake_digest}/en/overrides.js"
           expect(response.status).to eq(200)
           expect(response.body).to_not include("server.some_key", "server.some_MF")
 
@@ -144,12 +144,7 @@ RSpec.describe ExtraLocalesController do
             "{NUM_RESULTS, plural, one {1 result} other {many} }",
           )
 
-          SiteSetting.allow_user_locale = true
-          user = Fabricate(:user, locale: :fr)
-          sign_in(user)
-
-          get "/extra-locales/#{fake_digest}/overrides"
-          expect(response.status).to eq(200)
+          get ExtraLocalesController.url("overrides", locale: :fr)
 
           ctx = MiniRacer::Context.new
           ctx.eval("I18n = {};")
@@ -169,7 +164,7 @@ RSpec.describe ExtraLocalesController do
       before { JsLocaleHelper.stubs(:output_MF).with("en").returns("MF_TRANSLATIONS") }
 
       it "returns the translations properly" do
-        get "/extra-locales/#{fake_digest}/mf"
+        get ExtraLocalesController.url("mf")
         expect(response.body).to eq("MF_TRANSLATIONS")
       end
     end
@@ -177,28 +172,32 @@ RSpec.describe ExtraLocalesController do
 
   describe ".bundle_js_hash" do
     it "doesn't call bundle_js more than once for the same locale and bundle" do
-      I18n.locale = :de
-      ExtraLocalesController.expects(:bundle_js).with("admin").returns("admin_js DE").once
+      locale = :de
+      ExtraLocalesController.expects(:bundle_js).with("admin", locale:).returns("admin_js DE").once
       expected_hash_de = Digest::SHA1.hexdigest("admin_js DE")
 
-      expect(ExtraLocalesController.bundle_js_hash("admin")).to eq(expected_hash_de)
-      expect(ExtraLocalesController.bundle_js_hash("admin")).to eq(expected_hash_de)
+      expect(ExtraLocalesController.bundle_js_hash("admin", locale:)).to eq(expected_hash_de)
+      expect(ExtraLocalesController.bundle_js_hash("admin", locale:)).to eq(expected_hash_de)
 
-      I18n.locale = :fr
-      ExtraLocalesController.expects(:bundle_js).with("admin").returns("admin_js FR").once
+      locale = :fr
+      ExtraLocalesController.expects(:bundle_js).with("admin", locale:).returns("admin_js FR").once
       expected_hash_fr = Digest::SHA1.hexdigest("admin_js FR")
 
-      expect(ExtraLocalesController.bundle_js_hash("admin")).to eq(expected_hash_fr)
-      expect(ExtraLocalesController.bundle_js_hash("admin")).to eq(expected_hash_fr)
+      expect(ExtraLocalesController.bundle_js_hash("admin", locale:)).to eq(expected_hash_fr)
+      expect(ExtraLocalesController.bundle_js_hash("admin", locale:)).to eq(expected_hash_fr)
 
-      I18n.locale = :de
-      expect(ExtraLocalesController.bundle_js_hash("admin")).to eq(expected_hash_de)
+      locale = :de
+      expect(ExtraLocalesController.bundle_js_hash("admin", locale:)).to eq(expected_hash_de)
 
-      ExtraLocalesController.expects(:bundle_js).with("wizard").returns("wizard_js DE").once
+      ExtraLocalesController
+        .expects(:bundle_js)
+        .with("wizard", locale:)
+        .returns("wizard_js DE")
+        .once
       expected_hash_de = Digest::SHA1.hexdigest("wizard_js DE")
 
-      expect(ExtraLocalesController.bundle_js_hash("wizard")).to eq(expected_hash_de)
-      expect(ExtraLocalesController.bundle_js_hash("wizard")).to eq(expected_hash_de)
+      expect(ExtraLocalesController.bundle_js_hash("wizard", locale:)).to eq(expected_hash_de)
+      expect(ExtraLocalesController.bundle_js_hash("wizard", locale:)).to eq(expected_hash_de)
     end
   end
 
@@ -224,10 +223,10 @@ RSpec.describe ExtraLocalesController do
   end
 
   describe ".bundle_js_with_hash" do
-    before { described_class.stubs(:bundle_js).with("admin").returns("JS") }
+    before { described_class.stubs(:bundle_js).with("admin", locale: :en).returns("JS") }
 
     it "returns both JS and its hash for a given bundle" do
-      expect(described_class.bundle_js_with_hash("admin")).to eq(
+      expect(described_class.bundle_js_with_hash("admin", locale: :en)).to eq(
         ["JS", Digest::SHA1.hexdigest("JS")],
       )
     end
@@ -235,7 +234,9 @@ RSpec.describe ExtraLocalesController do
 
   describe ".url" do
     it "works" do
-      expect(ExtraLocalesController.url("admin")).to match(%r{\A/extra-locales/\h{40}\/admin\z})
+      expect(ExtraLocalesController.url("admin")).to match(
+        %r{\A/extra-locales/\h{40}/en/admin\.js\z},
+      )
     end
 
     it "includes subfolder path" do
@@ -256,5 +257,12 @@ RSpec.describe ExtraLocalesController do
         "https://cdn.example.com/extra-locales/",
       )
     end
+
+    it "includes locale correctly" do
+      expect(ExtraLocalesController.url("admin")).to include("/en/admin.js")
+      I18n.with_locale(:fr) do
+        expect(ExtraLocalesController.url("admin")).to include("/fr/admin.js")
+      end
+    end
   end
 end