diff --git a/guix/import/firefox.scm b/guix/import/firefox.scm
new file mode 100644
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+++ b/guix/import/firefox.scm
@@ -0,0 +1,47 @@
+;;; SPDX-License-Identifier: GPL-3.0-or-later
+;;; Copyright © 2025 Nicolas Graves <ngraves@ngraves.fr>
+
+;;; This file is not part of GNU Guix but requires this naming scheme
+;;; so that the %firefox-updater is properly read when using
+;;; `guix refresh -L$(pwd) firefox' in nonguix root.
+
+(define-module (guix import firefox)
+  #:use-module (guix import json)
+  #:use-module (guix memoization)
+  #:use-module (guix packages)
+  #:use-module (guix upstream)
+  #:export (%firefox-updater))
+
+(define firefox-json-url "https://product-details.mozilla.org/1.0/firefox_versions.json")
+
+(define firefox-versions
+  (memoize
+   (lambda _
+     (let ((alist (json-fetch firefox-json-url)))
+       (list (cons "firefox" (assoc-ref alist "LATEST_FIREFOX_VERSION"))
+             (cons "firefox-esr" (assoc-ref alist "FIREFOX_ESR")))))))
+
+(define* (latest-release package #:key (version #f) partial-version?)
+  "Return an <upstream-source> for the latest-release of PACKAGE."
+  (let* ((name (package-name package))
+         (version (or version (assoc-ref (firefox-versions) name))))
+    (upstream-source
+      (package name)
+      (version version)
+      (urls
+       (list (string-append "https://archive.mozilla.org/pub/firefox/releases/"
+                            version "/source/firefox-"
+                            version ".source.tar.xz"))))))
+
+(define (firefox-package? package)
+  "Return true if PACKAGE is Firefox."
+  (member (package-name package) (list "firefox" "firefox-esr")))
+
+(define %firefox-updater
+  (upstream-updater
+   (name 'firefox)
+   (description "Updater for Firefox packages")
+   (pred firefox-package?)
+   (import latest-release)))
+
+;;; firefox.scm ends here.