diff --git a/gnu/packages/librewolf.scm b/gnu/packages/librewolf.scm
index c84bcaf3ce..a400080dcb 100644
--- a/gnu/packages/librewolf.scm
+++ b/gnu/packages/librewolf.scm
@@ -93,6 +93,18 @@ (define-module (gnu packages librewolf)
   #:use-module (gnu packages xdisorg)
   #:use-module (gnu packages xorg))
 
+;; Define the versions of rust needed to build librewolf, trying to match
+;; upstream.  See the file taskcluster/kinds/toolchain/rust.yml at
+;; https://searchfox.org under the particular firefox release, like
+;; mozilla-esr102.
+;; 1.75 is the default in Guix, 1.77 is the minimum for Librewolf.
+(define rust-librewolf rust-1.77)
+
+;; Update this id with every update to its release date.
+;; It's used for cache validation and therefore can lead to strange bugs.
+;; ex: date '+%Y%m%d%H%M%S'
+(define %librewolf-build-id "20240626133423")
+
 (define (firefox-source-origin version hash)
   (origin
     (method url-fetch)
@@ -114,11 +126,14 @@ (define (librewolf-source-origin version hash)
 
 (define computed-origin-method (@@ (guix packages) computed-origin-method))
 
-(define librewolf-source
-  (let* ((ff-src (firefox-source-origin "126.0.1" "0fr679rcwshwpfxidc55b2xsn4pmrr7p9ix4rr2mv2k7kwsjcc7n"))
-         (version "126.0.1-1")
-         (lw-src (librewolf-source-origin version "0cac80073vkzd85ai9rbnwixs1h9bpy4dj2ri6jxdlqsy5d663km")))
-
+(define* (make-librewolf-source version #:key firefox-hash librewolf-hash)
+  (let* ((ff-src (firefox-source-origin
+                  (car (string-split version #\-))
+                  firefox-hash))
+         (version version)
+         (lw-src (librewolf-source-origin
+                  version
+                  librewolf-hash)))
     (origin
       (method computed-origin-method)
       (file-name (string-append "librewolf-" version ".source.tar.gz"))
@@ -162,11 +177,6 @@ (define librewolf-source
                  (("^ff_source_tarball:=.*")
                   (string-append "ff_source_tarball:=" #+ff-src)))
 
-               ;; Remove encoding_rs patch, it doesn't build with Rust 1.75.
-               (substitute* '("assets/patches.txt")
-                 (("patches/encoding_rs.patch\\\n$")
-                  ""))
-
                ;; Stage locales.
                (begin
                  (format #t "Staging locales...~%")
@@ -204,523 +214,521 @@ (define librewolf-source
                                          ".source.tar.gz")
                           #$output))))))))
 
-;; Define the versions of rust needed to build librewolf, trying to match
-;; upstream.  See the file taskcluster/ci/toolchain/rust.yml at
-;; https://searchfox.org under the particular firefox release, like
-;; mozilla-esr102.
-(define rust-librewolf rust) ; 1.75 is the default in Guix, 1.65 is the minimum.
-
-;; Update this id with every update to its release date.
-;; It's used for cache validation and therefore can lead to strange bugs.
-;; ex: date '+%Y%m%d%H%M%S'
-(define %librewolf-build-id "20240607212143")
-
 (define-public librewolf
-  (package
-    (name "librewolf")
-    (version "126.0.1-1")
-    (source librewolf-source)
-    (build-system gnu-build-system)
-    (arguments
-     (list
-      #:configure-flags #~(let ((clang #$(this-package-native-input "clang")))
-                            `("--enable-application=browser"
-
-                              ;; Configuration
-                              "--without-wasm-sandboxed-libraries"
-                              "--with-system-jpeg"
-                              "--with-system-zlib"
-                              "--with-system-png"
-                              "--with-system-webp"
-                              "--with-system-icu"
-                              "--with-system-libvpx"
-                              "--with-system-libevent"
-                              "--with-system-ffi"
-                              "--enable-system-pixman"
-                              "--enable-jemalloc"
-
-                              ;; see https://bugs.gnu.org/32833
-                              "--with-system-nspr"
-                              "--with-system-nss"
-
-                              ,(string-append "--with-clang-path=" clang
-                                              "/bin/clang")
-                              ,(string-append "--with-libclang-path=" clang
-                                              "/lib")
-
-                              ;; Distribution
-                              "--with-distribution-id=org.guix"
-                              "--with-app-name=librewolf"
-                              "--with-app-basename=LibreWolf"
-                              "--with-branding=browser/branding/librewolf"
-
-                              ;; Features
-                              "--disable-tests"
-                              "--disable-updater"
-                              "--enable-pulseaudio"
-                              "--disable-crashreporter"
-                              "--allow-addon-sideload"
-                              "--with-unsigned-addon-scopes=app,system"
-                              "--disable-eme"
-
-                              ;; Build details
-                              "--disable-debug"
-                              "--enable-rust-simd"
-                              "--enable-release"
-                              "--enable-optimize"
-                              "--enable-strip"
-                              "--enable-hardening"
-                              "--disable-elf-hack"))
-      #:imported-modules %cargo-utils-modules
-      #:modules `((ice-9 regex)
-                  (ice-9 string-fun)
-                  (ice-9 ftw)
-                  (srfi srfi-1)
-                  (srfi srfi-26)
-                  (rnrs bytevectors)
-                  (rnrs io ports)
-                  (guix elf)
-                  (guix build gremlin)
-                  ,@%gnu-build-system-modules)
-      #:phases #~(modify-phases %standard-phases
-                   (add-after 'unpack 'fix-preferences
-                     (lambda* (#:key inputs #:allow-other-keys)
-                       (let ((port (open-file "browser/app/profile/firefox.js"
-                                    "a")))
-                         (define (write-setting key value)
-                           (format port "~%pref(\"~a\", ~a);~%" key value)
-                           (format #t
+  (let ((version "127.0.2-2"))
+    (package
+      (name "librewolf")
+      (version version)
+      (source (make-librewolf-source
+               version
+               #:firefox-hash
+               "1s73fdp7k60058ylyvlixq13k5hfbmj6k1y42fmzqlpg7n62lyqb"
+               #:librewolf-hash
+               "1f4xz496x1nf7lmvk50hakj9p6q0kzxl5f9s2k0b6kczvyc8gw5n"))
+
+      (build-system gnu-build-system)
+      (arguments
+       (list
+        #:configure-flags
+        #~(let ((clang #$(this-package-native-input "clang")))
+            `("--enable-application=browser"
+
+              ;; Configuration
+              "--without-wasm-sandboxed-libraries"
+              "--with-system-jpeg"
+              "--with-system-zlib"
+              "--with-system-png"
+              "--with-system-webp"
+              "--with-system-icu"
+              "--with-system-libvpx"
+              "--with-system-libevent"
+              "--with-system-ffi"
+              "--enable-system-pixman"
+              "--enable-jemalloc"
+
+              ;; see https://bugs.gnu.org/32833
+              "--with-system-nspr"
+              "--with-system-nss"
+
+              ,(string-append "--with-clang-path=" clang
+                              "/bin/clang")
+              ,(string-append "--with-libclang-path=" clang
+                              "/lib")
+
+              ;; Distribution
+              "--with-distribution-id=org.guix"
+              "--with-app-name=librewolf"
+              "--with-app-basename=LibreWolf"
+              "--with-branding=browser/branding/librewolf"
+
+              ;; Features
+              "--disable-tests"
+              "--disable-updater"
+              "--enable-pulseaudio"
+              "--disable-crashreporter"
+              "--allow-addon-sideload"
+              "--with-unsigned-addon-scopes=app,system"
+              "--disable-eme"
+
+              ;; Build details
+              "--disable-debug"
+              "--enable-rust-simd"
+              "--enable-release"
+              "--enable-optimize"
+              "--enable-strip"
+              "--enable-hardening"
+              "--disable-elf-hack"))
+        #:imported-modules %cargo-utils-modules
+        #:modules `((ice-9 regex)
+                    (ice-9 string-fun)
+                    (ice-9 ftw)
+                    (srfi srfi-1)
+                    (srfi srfi-26)
+                    (rnrs bytevectors)
+                    (rnrs io ports)
+                    (guix elf)
+                    (guix build gremlin)
+                    ,@%gnu-build-system-modules)
+        #:phases
+        #~(modify-phases %standard-phases
+            (add-after 'unpack 'fix-preferences
+              (lambda* (#:key inputs #:allow-other-keys)
+                (let ((port (open-file "browser/app/profile/firefox.js"
+                                       "a")))
+                  (define (write-setting key value)
+                    (format port "~%pref(\"~a\", ~a);~%" key value)
+                    (format #t
                             "fix-preferences: setting value of ~a to ~a~%" key
                             value))
 
-                         ;; We should allow the sandbox to read the store directory,
-                         ;; because the sandbox has access to /usr on FHS distros.
-                         (write-setting
-                          "security.sandbox.content.read_path_whitelist"
-                          (string-append "\""
-                                         (%store-directory) "/\""))
-
-                         ;; XDG settings should be managed by Guix.
-                         (write-setting "browser.shell.checkDefaultBrowser"
-                                        "false")
-                         (close-port port))))
-                   (add-after 'fix-preferences 'fix-ffmpeg-runtime-linker
-                     (lambda* (#:key inputs #:allow-other-keys)
-                       (let* ((ffmpeg (assoc-ref inputs "ffmpeg"))
-                              (libavcodec (string-append ffmpeg
-                                                         "/lib/libavcodec.so")))
-                         ;; Arrange to load libavcodec.so by its absolute file name.
-                         (substitute* "dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp"
-                           (("libavcodec\\.so")
-                            libavcodec)))))
-                   (add-after 'patch-source-shebangs 'patch-cargo-checksums
-                     (lambda _
-                       (use-modules (guix build cargo-utils))
-                       (let ((null-hash
-                              ;; This is the SHA256 output of an empty string.
-                              (string-append
-                               "e3b0c44298fc1c149afbf4c8996fb924"
-                               "27ae41e4649b934ca495991b7852b855")))
-                         (for-each (lambda (file)
-                                     (format #t
+                  ;; We should allow the sandbox to read the store directory,
+                  ;; because the sandbox has access to /usr on FHS distros.
+                  (write-setting
+                   "security.sandbox.content.read_path_whitelist"
+                   (string-append "\""
+                                  (%store-directory) "/\""))
+
+                  ;; XDG settings should be managed by Guix.
+                  (write-setting "browser.shell.checkDefaultBrowser"
+                                 "false")
+                  (close-port port))))
+            (add-after 'fix-preferences 'fix-ffmpeg-runtime-linker
+              (lambda* (#:key inputs #:allow-other-keys)
+                (let* ((ffmpeg (assoc-ref inputs "ffmpeg"))
+                       (libavcodec (string-append ffmpeg
+                                                  "/lib/libavcodec.so")))
+                  ;; Arrange to load libavcodec.so by its absolute file name.
+                  (substitute* "dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp"
+                    (("libavcodec\\.so")
+                     libavcodec)))))
+            (add-after 'patch-source-shebangs 'patch-cargo-checksums
+              (lambda _
+                (use-modules (guix build cargo-utils))
+                (let ((null-hash
+                       ;; This is the SHA256 output of an empty string.
+                       (string-append
+                        "e3b0c44298fc1c149afbf4c8996fb924"
+                        "27ae41e4649b934ca495991b7852b855")))
+                  (for-each (lambda (file)
+                              (format #t
                                       "patch-cargo-checksums: patching checksums in ~a~%"
                                       file)
-                                     (substitute* file
-                                       (("(checksum = )\".*\"" all name)
-                                        (string-append name "\"" null-hash
-                                                       "\""))))
-                                   (find-files "." "Cargo\\.lock$"))
-                         (for-each generate-all-checksums
-                                   '("build"
-                                     "dom/media"
-                                     "dom/webauthn"
-                                     "gfx"
-                                     "intl"
-                                     "js"
-                                     "media"
-                                     "modules"
-                                     "mozglue/static/rust"
-                                     "netwerk"
-                                     "remote"
-                                     "security/manager/ssl"
-                                     "servo"
-                                     "storage"
-                                     "third_party/rust"
-                                     "toolkit"
-                                     "xpcom/rust"
-                                     "services")))))
-                   (add-after 'patch-cargo-checksums 'remove-cargo-frozen-flag
-                     (lambda _
-                       ;; Remove --frozen flag from cargo invokation, otherwise it'll
-                       ;; complain that it's not able to change Cargo.lock.
-                       ;; https://bugzilla.mozilla.org/show_bug.cgi?id=1726373
-                       (substitute* "build/RunCbindgen.py"
-                         (("args.append\\(\"--frozen\"\\)") "pass"))))
-                   (delete 'bootstrap)
-                   (add-before 'configure 'patch-SpeechDispatcherService.cpp
-                     (lambda _
-                       (let* ((lib "libspeechd.so.2")
-                              (file (string-append
-                                     "dom/media/webspeech/synth/"
-                                     "speechd/SpeechDispatcherService.cpp"))
-                              (old-content (call-with-input-file file
-                                             get-string-all)))
-                         (substitute
-                          file
-                          `((,(format #f "~s" lib) unquote
-                             (lambda (line _)
-                               (string-replace-substring
-                                line lib
-                                (string-append #$speech-dispatcher
-                                               "/lib/" lib))))))
-                         (if (string=? old-content
-                                       (call-with-input-file file
-                                         get-string-all))
-                             (error
-                              "substitute did nothing, phase requires an update")))))
-                   (add-before 'configure 'set-build-id
-                     ;; Build will write the timestamp to output, which is harmful
-                     ;; for reproducibility, so change it to a fixed date.  Use a
-                     ;; separate phase for easier modification with inherit.
-                     (lambda _
-                       (setenv "MOZ_BUILD_DATE"
-                               #$%librewolf-build-id)))
-                   (replace 'configure
-                     (lambda* (#:key inputs outputs configure-flags
-                               #:allow-other-keys)
-                       (setenv "AUTOCONF"
-                               (string-append (assoc-ref inputs "autoconf")
-                                              "/bin/autoconf"))
-                       (setenv "SHELL"
-                               (which "bash"))
-                       (setenv "CONFIG_SHELL"
-                               (which "bash"))
-                       (setenv "MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE"
-                               "system")
-                       ;; This should use the host info probably (does it
-                       ;; build on non-x86_64 though?)
-                       (setenv "GUIX_PYTHONPATH"
-                               (string-append (getcwd)
-                                "/obj-x86_64-pc-linux-gnu/_virtualenvs/build"))
-
-                       ;; Use Clang, Clang is 2x faster than GCC
-                       (setenv "AR" "llvm-ar")
-                       (setenv "NM" "llvm-nm")
-                       (setenv "CC" "clang")
-                       (setenv "CXX" "clang++")
-                       (setenv "MOZ_NOSPAM" "1")
-                       (setenv "MOZ_APP_NAME" "librewolf")
-
-                       (setenv "MOZBUILD_STATE_PATH"
-                               (getcwd))
-
-                       (let* ((mozconfig (string-append (getcwd) "/mozconfig"))
-                              (out (assoc-ref outputs "out"))
-                              (flags (cons (string-append "--prefix=" out)
-                                           configure-flags)))
-                         (format #t "build directory: ~s~%"
-                                 (getcwd))
-                         (format #t "configure flags: ~s~%" flags)
-
-                         (define write-flags
-                           (lambda flags
-                             (display (string-join (map (cut string-append
-                                                         "ac_add_options " <>)
-                                                        flags) "\n"))
-                             (display "\n")))
-                         (with-output-to-file mozconfig
-                           (lambda ()
-                             (apply write-flags flags)
-                             ;; The following option unsets Telemetry
-                             ;; Reporting. With the Addons Fiasco,
-                             ;; Mozilla was found to be collecting
-                             ;; user's data, including saved passwords
-                             ;; and web form data, without users
-                             ;; consent. Mozilla was also found
-                             ;; shipping updates to systems without
-                             ;; the user's knowledge or permission.
-                             ;; As a result of this, use the following
-                             ;; command to permanently disable
-                             ;; telemetry reporting.
-                             (display "unset MOZ_TELEMETRY_REPORTING\n")
-                             (display "mk_add_options MOZ_CRASHREPORTER=0\n")
-                             (display "mk_add_options MOZ_DATA_REPORTING=0\n")
-                             (display
-                              "mk_add_options MOZ_SERVICES_HEALTHREPORT=0")
-                             (display
-                              "mk_add_options MOZ_TELEMETRY_REPORTING=0")))
-                         (setenv "MOZCONFIG" mozconfig))
-                       (invoke "./mach" "configure")))
-                   (add-before 'build 'fix-addons-placeholder
-                     (lambda _
-                       (substitute* "toolkit/locales/en-US/toolkit/about/aboutAddons.ftl"
-                         (("addons.mozilla.org")
-                          "gnuzilla.gnu.org"))))
-                   (replace 'build
-                     (lambda* (#:key (make-flags '())
-                               (parallel-build? #t) #:allow-other-keys)
-                       (apply invoke "./mach" "build"
-                              ;; mach will use parallel build if possible by default
-                              `(,@(if parallel-build?
-                                      '()
-                                      '("-j1")) ,@make-flags))))
-                   (add-after 'build 'neutralise-store-references
-                     (lambda _
-                       ;; Mangle the store references to compilers &
-                       ;; other build tools in about:buildconfig,
-                       ;; reducing the package's closure by 1 GiB on
-                       ;; x86-64.
-                       (let* ((build-dir (car (scandir "."
-                                                       (cut string-prefix?
-                                                            "obj-" <>))))
-                              (file (string-append build-dir
-                                     "/dist/bin/chrome/toolkit/"
-                                     "content/global/buildconfig.html")))
-                         (substitute* file
-                           (((format #f "(~a/)([0-9a-df-np-sv-z]{32})"
-                                     (regexp-quote (%store-directory)))
-                             _ store hash)
-                            (string-append store
-                             (string-take hash 8)
-                             "<!-- Guix: not a runtime dependency -->"
-                             (string-drop hash 8)))))))
-                   (replace 'install
-                     (lambda _
-                       (invoke "./mach" "install")))
-                   (add-after 'install 'remove-duplicate-bin
-                     (lambda* (#:key outputs #:allow-other-keys)
-                       (delete-file (string-append #$output
-                                     "/lib/librewolf/librewolf-bin"))))
-                   (add-after 'install 'wrap-glxtest
-                     ;; glxtest uses dlopen() to load mesa and pci
-                     ;; libs, wrap it to set LD_LIBRARY_PATH.
-                     (lambda* (#:key inputs outputs #:allow-other-keys)
-                       (let* ((out (assoc-ref outputs "out"))
-                              (lib (string-append out "/lib"))
-                              (libs (map
-                                     (lambda (lib-name)
-                                       (string-append (assoc-ref inputs
-                                                                 lib-name)
-                                                      "/lib"))
-                                     '("mesa" "pciutils"))))
-                         (wrap-program (car (find-files lib "^glxtest$"))
-                           `("LD_LIBRARY_PATH" prefix ,libs)))))
-                   (add-after 'install 'patch-config
-                     (lambda* (#:key inputs #:allow-other-keys)
-                       (let ((lib (string-append #$output "/lib/librewolf"))
-                             (config-file "librewolf.cfg"))
-
-                         ;; Required for Guix packaged extensions
-                         ;; SCOPE_PROFILE=1, SCOPE_APPLICATION=4, SCOPE_SYSTEM=8
-                         ;; Default is 5.
-                         (substitute* (in-vicinity lib config-file)
-                           (("defaultPref\\(\"extensions.enabledScopes\", 5\\)")
-                            "defaultPref(\"extensions.enabledScopes\", 13)"))
-                         ;; Use Mozzarella addons repo.
-                         (call-with-port
-                             (open-file
-                              (in-vicinity lib config-file)
-                              "a")
-                           (lambda (port)
-                             ;; Add-ons panel (see settings.js in Icecat source).
-                             (for-each
-                              (lambda (pref)
-                                (format port
-                                        "defaultPref(~s, ~s);~%"
-                                        (car pref)
-                                        (cdr pref)))
-                              `(("extensions.getAddons.search.browseURL"
-                                 ,(string-append
-                                   "https://gnuzilla.gnu.org/mozzarella/"
-                                   "search.php?q=%TERMS%"))
-                                ("extensions.getAddons.get.url" .
-                                 "https://gnuzilla.gnu.org/mozzarella")
-                                ("extensions.getAddons.link.url" .
-                                 "https://gnuzilla.gnu.org/mozzarella")
-                                ("extensions.getAddons.discovery.api_url" .
-                                 "https://gnuzilla.gnu.org/mozzarella")
-                                ("extensions.getAddons.langpacks.url" .
-                                 "https://gnuzilla.gnu.org/mozzarella")
-                                ("lightweightThemes.getMoreURL" .
-                                 "https://gnuzilla.gnu.org/mozzarella"))))))))
-                   (add-after 'install 'wrap-program
-                     (lambda* (#:key inputs outputs #:allow-other-keys)
-                       ;; The following two functions are from Guix's icecat package in
-                       ;; (gnu packages gnuzilla).  See commit
-                       ;; b7a0935420ee630a29b7e5ac73a32ba1eb24f00b.
-                       (define (runpath-of lib)
-                         (call-with-input-file lib
-                           (compose elf-dynamic-info-runpath elf-dynamic-info
-                                    parse-elf get-bytevector-all)))
-                       (define (runpaths-of-input label)
-                         (let* ((dir (string-append (assoc-ref inputs label)
-                                                    "/lib"))
-                                (libs (find-files dir "\\.so$")))
-                           (append-map runpath-of libs)))
-                       (let* ((out (assoc-ref outputs "out"))
-                              (lib (string-append out "/lib"))
-                              (libs (map
-                                     (lambda (lib-name)
-                                       (string-append (assoc-ref inputs
-                                                                 lib-name)
-                                                      "/lib"))
-                                     '("mesa" "libpng-apng" "libnotify" "libva"
-                                       "pulseaudio" "gtk+" "pipewire"
-                                       ;; For U2F and WebAuthn
-                                       "eudev")))
-
-                              ;; VA-API is run in the RDD (Remote Data Decoder) sandbox
-                              ;; and must be explicitly given access to files it needs.
-                              ;; Rather than adding the whole store (as Nix had
-                              ;; upstream do, see
-                              ;; <https://github.com/NixOS/nixpkgs/pull/165964> and
-                              ;; linked upstream patches), we can just follow the
-                              ;; runpaths of the needed libraries to add everything to
-                              ;; LD_LIBRARY_PATH.  These will then be accessible in the
-                              ;; RDD sandbox.
-                              (rdd-whitelist (map (cut string-append <> "/")
-                                                  (delete-duplicates (append-map
-                                                                      runpaths-of-input
-                                                                      '("mesa"
-                                                                        "ffmpeg")))))
-                              (gtk-share (string-append (assoc-ref inputs
-                                                                   "gtk+")
-                                                        "/share")))
-                         (wrap-program (car (find-files lib "^librewolf$"))
-                           `("LD_LIBRARY_PATH" prefix
-                             (,@libs ,@rdd-whitelist))
-                           `("XDG_DATA_DIRS" prefix
-                             (,gtk-share))
-                           `("MOZ_LEGACY_PROFILES" =
-                             ("1"))
-                           `("MOZ_ALLOW_DOWNGRADE" =
-                             ("1"))))))
-                   (add-after 'wrap-program 'install-desktop-entry
-                     (lambda* (#:key outputs #:allow-other-keys)
-                       (let* ((desktop-file
-                               "taskcluster/docker/firefox-snap/firefox.desktop")
-                              (applications (string-append #$output
-                                             "/share/applications")))
-                         (substitute* desktop-file
-                           (("^Exec=firefox")
-                            (string-append "Exec="
-                                           #$output "/bin/librewolf"))
-                           ;; "Firefox" -> "LibreWolf" everywhere
-                           (("Firefox")
-                            "LibreWolf")
-                           ;; Remove non-Latin translations.
-                           (("^Name\\[(ar|bn)\\].*$")
-                            "")
-                           (("^Icon=.*")
-                            (string-append "Icon="
-                             #$output
-                             "/share/icons/hicolor/128x128/apps/librewolf.png
+                              (substitute* file
+                                (("(checksum = )\".*\"" all name)
+                                 (string-append name "\"" null-hash
+                                                "\""))))
+                            (find-files "." "Cargo\\.lock$"))
+                  (for-each generate-all-checksums
+                            '("build"
+                              "dom/media"
+                              "dom/webauthn"
+                              "gfx"
+                              "intl"
+                              "js"
+                              "media"
+                              "modules"
+                              "mozglue/static/rust"
+                              "netwerk"
+                              "remote"
+                              "security/manager/ssl"
+                              "servo"
+                              "storage"
+                              "third_party/rust"
+                              "toolkit"
+                              "xpcom/rust"
+                              "services")))))
+            (add-after 'patch-cargo-checksums 'remove-cargo-frozen-flag
+              (lambda _
+                ;; Remove --frozen flag from cargo invokation, otherwise it'll
+                ;; complain that it's not able to change Cargo.lock.
+                ;; https://bugzilla.mozilla.org/show_bug.cgi?id=1726373
+                (substitute* "build/RunCbindgen.py"
+                  (("args.append\\(\"--frozen\"\\)") "pass"))))
+            (delete 'bootstrap)
+            (add-before 'configure 'patch-SpeechDispatcherService.cpp
+              (lambda _
+                (let* ((lib "libspeechd.so.2")
+                       (file (string-append
+                              "dom/media/webspeech/synth/"
+                              "speechd/SpeechDispatcherService.cpp"))
+                       (old-content (call-with-input-file file
+                                      get-string-all)))
+                  (substitute
+                   file
+                   `((,(format #f "~s" lib) unquote
+                      (lambda (line _)
+                        (string-replace-substring
+                         line lib
+                         (string-append #$speech-dispatcher
+                                        "/lib/" lib))))))
+                  (if (string=? old-content
+                                (call-with-input-file file
+                                  get-string-all))
+                      (error
+                       "substitute did nothing, phase requires an update")))))
+            (add-before 'configure 'set-build-id
+              ;; Build will write the timestamp to output, which is harmful
+              ;; for reproducibility, so change it to a fixed date.  Use a
+              ;; separate phase for easier modification with inherit.
+              (lambda _
+                (setenv "MOZ_BUILD_DATE"
+                        #$%librewolf-build-id)))
+            (replace 'configure
+              (lambda* (#:key inputs outputs configure-flags
+                        #:allow-other-keys)
+                (setenv "AUTOCONF"
+                        (string-append (assoc-ref inputs "autoconf")
+                                       "/bin/autoconf"))
+                (setenv "SHELL"
+                        (which "bash"))
+                (setenv "CONFIG_SHELL"
+                        (which "bash"))
+                (setenv "MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE"
+                        "system")
+                ;; This should use the host info probably (does it
+                ;; build on non-x86_64 though?)
+                (setenv "GUIX_PYTHONPATH"
+                        (string-append (getcwd)
+                                       "/obj-x86_64-pc-linux-gnu/_virtualenvs/build"))
+
+                ;; Use Clang, Clang is 2x faster than GCC
+                (setenv "AR" "llvm-ar")
+                (setenv "NM" "llvm-nm")
+                (setenv "CC" "clang")
+                (setenv "CXX" "clang++")
+                (setenv "MOZ_NOSPAM" "1")
+                (setenv "MOZ_APP_NAME" "librewolf")
+
+                (setenv "MOZBUILD_STATE_PATH"
+                        (getcwd))
+
+                (let* ((mozconfig (string-append (getcwd) "/mozconfig"))
+                       (out (assoc-ref outputs "out"))
+                       (flags (cons (string-append "--prefix=" out)
+                                    configure-flags)))
+                  (format #t "build directory: ~s~%"
+                          (getcwd))
+                  (format #t "configure flags: ~s~%" flags)
+
+                  (define write-flags
+                    (lambda flags
+                      (display (string-join (map (cut string-append
+                                                      "ac_add_options " <>)
+                                                 flags) "\n"))
+                      (display "\n")))
+                  (with-output-to-file mozconfig
+                    (lambda ()
+                      (apply write-flags flags)
+                      ;; The following option unsets Telemetry
+                      ;; Reporting. With the Addons Fiasco,
+                      ;; Mozilla was found to be collecting
+                      ;; user's data, including saved passwords
+                      ;; and web form data, without users
+                      ;; consent. Mozilla was also found
+                      ;; shipping updates to systems without
+                      ;; the user's knowledge or permission.
+                      ;; As a result of this, use the following
+                      ;; command to permanently disable
+                      ;; telemetry reporting.
+                      (display "unset MOZ_TELEMETRY_REPORTING\n")
+                      (display "mk_add_options MOZ_CRASHREPORTER=0\n")
+                      (display "mk_add_options MOZ_DATA_REPORTING=0\n")
+                      (display
+                       "mk_add_options MOZ_SERVICES_HEALTHREPORT=0")
+                      (display
+                       "mk_add_options MOZ_TELEMETRY_REPORTING=0")))
+                  (setenv "MOZCONFIG" mozconfig))
+                (invoke "./mach" "configure")))
+            (add-before 'build 'fix-addons-placeholder
+              (lambda _
+                (substitute* "toolkit/locales/en-US/toolkit/about/aboutAddons.ftl"
+                  (("addons.mozilla.org")
+                   "gnuzilla.gnu.org"))))
+            (replace 'build
+              (lambda* (#:key (make-flags '())
+                        (parallel-build? #t) #:allow-other-keys)
+                (apply invoke "./mach" "build"
+                       ;; mach will use parallel build if possible by default
+                       `(,@(if parallel-build?
+                               '()
+                               '("-j1")) ,@make-flags))))
+            (add-after 'build 'neutralise-store-references
+              (lambda _
+                ;; Mangle the store references to compilers &
+                ;; other build tools in about:buildconfig,
+                ;; reducing the package's closure by 1 GiB on
+                ;; x86-64.
+                (let* ((build-dir (car (scandir "."
+                                                (cut string-prefix?
+                                                     "obj-" <>))))
+                       (file (string-append build-dir
+                                            "/dist/bin/chrome/toolkit/"
+                                            "content/global/buildconfig.html")))
+                  (substitute* file
+                    (((format #f "(~a/)([0-9a-df-np-sv-z]{32})"
+                              (regexp-quote (%store-directory)))
+                      _ store hash)
+                     (string-append store
+                                    (string-take hash 8)
+                                    "<!-- Guix: not a runtime dependency -->"
+                                    (string-drop hash 8)))))))
+            (replace 'install
+              (lambda _
+                (invoke "./mach" "install")))
+            (add-after 'install 'remove-duplicate-bin
+              (lambda* (#:key outputs #:allow-other-keys)
+                (delete-file (string-append #$output
+                                            "/lib/librewolf/librewolf-bin"))))
+            (add-after 'install 'wrap-glxtest
+              ;; glxtest uses dlopen() to load mesa and pci
+              ;; libs, wrap it to set LD_LIBRARY_PATH.
+              (lambda* (#:key inputs outputs #:allow-other-keys)
+                (let* ((out (assoc-ref outputs "out"))
+                       (lib (string-append out "/lib"))
+                       (libs (map
+                              (lambda (lib-name)
+                                (string-append (assoc-ref inputs
+                                                          lib-name)
+                                               "/lib"))
+                              '("mesa" "pciutils"))))
+                  (wrap-program (car (find-files lib "^glxtest$"))
+                    `("LD_LIBRARY_PATH" prefix ,libs)))))
+            (add-after 'install 'patch-config
+              (lambda* (#:key inputs #:allow-other-keys)
+                (let ((lib (string-append #$output "/lib/librewolf"))
+                      (config-file "librewolf.cfg"))
+
+                  ;; Required for Guix packaged extensions
+                  ;; SCOPE_PROFILE=1, SCOPE_APPLICATION=4, SCOPE_SYSTEM=8
+                  ;; Default is 5.
+                  (substitute* (in-vicinity lib config-file)
+                    (("defaultPref\\(\"extensions.enabledScopes\", 5\\)")
+                     "defaultPref(\"extensions.enabledScopes\", 13)"))
+                  ;; Use Mozzarella addons repo.
+                  (call-with-port
+                      (open-file
+                       (in-vicinity lib config-file)
+                       "a")
+                    (lambda (port)
+                      ;; Add-ons panel (see settings.js in Icecat source).
+                      (for-each
+                       (lambda (pref)
+                         (format port
+                                 "defaultPref(~s, ~s);~%"
+                                 (car pref)
+                                 (cdr pref)))
+                       `(("extensions.getAddons.search.browseURL"
+                          ,(string-append
+                            "https://gnuzilla.gnu.org/mozzarella/"
+                            "search.php?q=%TERMS%"))
+                         ("extensions.getAddons.get.url" .
+                          "https://gnuzilla.gnu.org/mozzarella")
+                         ("extensions.getAddons.link.url" .
+                          "https://gnuzilla.gnu.org/mozzarella")
+                         ("extensions.getAddons.discovery.api_url" .
+                          "https://gnuzilla.gnu.org/mozzarella")
+                         ("extensions.getAddons.langpacks.url" .
+                          "https://gnuzilla.gnu.org/mozzarella")
+                         ("lightweightThemes.getMoreURL" .
+                          "https://gnuzilla.gnu.org/mozzarella"))))))))
+            (add-after 'install 'wrap-program
+              (lambda* (#:key inputs outputs #:allow-other-keys)
+                ;; The following two functions are from Guix's icecat package in
+                ;; (gnu packages gnuzilla).  See commit
+                ;; b7a0935420ee630a29b7e5ac73a32ba1eb24f00b.
+                (define (runpath-of lib)
+                  (call-with-input-file lib
+                    (compose elf-dynamic-info-runpath elf-dynamic-info
+                             parse-elf get-bytevector-all)))
+                (define (runpaths-of-input label)
+                  (let* ((dir (string-append (assoc-ref inputs label)
+                                             "/lib"))
+                         (libs (find-files dir "\\.so$")))
+                    (append-map runpath-of libs)))
+                (let* ((out (assoc-ref outputs "out"))
+                       (lib (string-append out "/lib"))
+                       (libs (map
+                              (lambda (lib-name)
+                                (string-append (assoc-ref inputs
+                                                          lib-name)
+                                               "/lib"))
+                              '("mesa" "libpng-apng" "libnotify" "libva"
+                                "pulseaudio" "gtk+" "pipewire"
+                                ;; For U2F and WebAuthn
+                                "eudev")))
+
+                       ;; VA-API is run in the RDD (Remote Data Decoder) sandbox
+                       ;; and must be explicitly given access to files it needs.
+                       ;; Rather than adding the whole store (as Nix had
+                       ;; upstream do, see
+                       ;; <https://github.com/NixOS/nixpkgs/pull/165964> and
+                       ;; linked upstream patches), we can just follow the
+                       ;; runpaths of the needed libraries to add everything to
+                       ;; LD_LIBRARY_PATH.  These will then be accessible in the
+                       ;; RDD sandbox.
+                       (rdd-whitelist (map (cut string-append <> "/")
+                                           (delete-duplicates (append-map
+                                                               runpaths-of-input
+                                                               '("mesa"
+                                                                 "ffmpeg")))))
+                       (gtk-share (string-append (assoc-ref inputs
+                                                            "gtk+")
+                                                 "/share")))
+                  (wrap-program (car (find-files lib "^librewolf$"))
+                    `("LD_LIBRARY_PATH" prefix
+                      (,@libs ,@rdd-whitelist))
+                    `("XDG_DATA_DIRS" prefix
+                      (,gtk-share))
+                    `("MOZ_LEGACY_PROFILES" =
+                      ("1"))
+                    `("MOZ_ALLOW_DOWNGRADE" =
+                      ("1"))))))
+            (add-after 'wrap-program 'install-desktop-entry
+              (lambda* (#:key outputs #:allow-other-keys)
+                (let* ((desktop-file
+                        "taskcluster/docker/firefox-snap/firefox.desktop")
+                       (applications (string-append #$output
+                                                    "/share/applications")))
+                  (substitute* desktop-file
+                    (("^Exec=firefox")
+                     (string-append "Exec="
+                                    #$output "/bin/librewolf"))
+                    ;; "Firefox" -> "LibreWolf" everywhere
+                    (("Firefox")
+                     "LibreWolf")
+                    ;; Remove non-Latin translations.
+                    (("^Name\\[(ar|bn)\\].*$")
+                     "")
+                    (("^Icon=.*")
+                     (string-append "Icon="
+                                    #$output
+                                    "/share/icons/hicolor/128x128/apps/librewolf.png
 "))
-                           ;; These commands were changed.
-                           (("-NewWindow")
-                            "-new-window")
-                           (("-NewPrivateWindow")
-                            "-new-private-window")
-                           (("StartupNotify=true")
-                            "StartupNotify=true
+                    ;; These commands were changed.
+                    (("-NewWindow")
+                     "-new-window")
+                    (("-NewPrivateWindow")
+                     "-new-private-window")
+                    (("StartupNotify=true")
+                     "StartupNotify=true
 StartupWMClass=Navigator"))
-                         (copy-file desktop-file "librewolf.desktop")
-                         (install-file "librewolf.desktop" applications))))
-                   (add-after 'install-desktop-entry 'install-icons
-                     (lambda* (#:key outputs #:allow-other-keys)
-                       (let ((icon-source-dir (string-append #$output
-                                               "/lib/librewolf/browser/"
-                                               "chrome/icons/default")))
-                         (for-each (lambda (size)
-                                     (let ((dest (string-append #$output
-                                                  "/share/icons/hicolor/"
-                                                  size
-                                                  "x"
-                                                  size
-                                                  "/apps")))
-                                       (mkdir-p dest)
-                                       (symlink (string-append icon-source-dir
-                                                 "/default" size ".png")
-                                                (string-append dest
-                                                 "/librewolf.png"))))
-                                   '("16" "32" "48" "64" "128"))))))
-
-      ;; Test will significantly increase build time but with little rewards.
-      #:tests? #f
-
-      ;; WARNING: Parallel build will consume lots of memory!
-      ;; If you have encountered OOM issue in build phase, try disable it.
-      #:parallel-build? #t
-
-      ;; Some dynamic lib was determined at runtime, so rpath check may fail.
-      #:validate-runpath? #f))
-    (inputs (list bash-minimal
-                  bzip2
-                  cairo
-                  cups
-                  dbus-glib
-                  freetype
-                  ffmpeg
-                  gdk-pixbuf
-                  glib
-                  gtk+
-                  gtk+-2
-                  hunspell
-                  icu4c-73
-                  jemalloc
-                  libcanberra
-                  libevent
-                  libffi
-                  libgnome
-                  libjpeg-turbo
-                  libnotify
-                  libpng-apng
-                  libva
-                  libvpx
-                  libwebp
-                  libxcomposite
-                  libxft
-                  libxinerama
-                  libxscrnsaver
-                  libxt
-                  mesa
-                  mit-krb5
-                  nspr
-                  nss/fixed
-                  pango
-                  pciutils
-                  pipewire
-                  pixman
-                  pulseaudio
-                  speech-dispatcher
-                  sqlite
-                  startup-notification
-                  eudev
-                  unzip
-                  zip
-                  zlib))
-    (native-inputs (list alsa-lib
-                         autoconf-2.13
-                         `(,rust-librewolf "cargo")
-                         clang-18
-                         llvm-18
-                         m4
-                         nasm
-                         node-lts
-                         perl
-                         pkg-config
-                         python
-                         rust-librewolf
-                         rust-cbindgen-0.26
-                         which
-                         yasm))
-    (home-page "https://librewolf.net/")
-    (synopsis
-     "Custom version of Firefox, focused on privacy, security and freedom")
-    (description
-     "LibreWolf is designed to increase protection against tracking and
+                  (copy-file desktop-file "librewolf.desktop")
+                  (install-file "librewolf.desktop" applications))))
+            (add-after 'install-desktop-entry 'install-icons
+              (lambda* (#:key outputs #:allow-other-keys)
+                (let ((icon-source-dir (string-append #$output
+                                                      "/lib/librewolf/browser/"
+                                                      "chrome/icons/default")))
+                  (for-each (lambda (size)
+                              (let ((dest (string-append #$output
+                                                         "/share/icons/hicolor/"
+                                                         size
+                                                         "x"
+                                                         size
+                                                         "/apps")))
+                                (mkdir-p dest)
+                                (symlink (string-append icon-source-dir
+                                                        "/default" size ".png")
+                                         (string-append dest
+                                                        "/librewolf.png"))))
+                            '("16" "32" "48" "64" "128"))))))
+
+        ;; Test will significantly increase build time but with little rewards.
+        #:tests? #f
+
+        ;; WARNING: Parallel build will consume lots of memory!
+        ;; If you have encountered OOM issue in build phase, try disable it.
+        #:parallel-build? #t
+
+        ;; Some dynamic lib was determined at runtime, so rpath check may fail.
+        #:validate-runpath? #f))
+      (inputs (list bash-minimal
+                    bzip2
+                    cairo
+                    cups
+                    dbus-glib
+                    freetype
+                    ffmpeg
+                    gdk-pixbuf
+                    glib
+                    gtk+
+                    gtk+-2
+                    hunspell
+                    icu4c-73
+                    jemalloc
+                    libcanberra
+                    libevent
+                    libffi
+                    libgnome
+                    libjpeg-turbo
+                    libnotify
+                    libpng-apng
+                    libva
+                    libvpx
+                    libwebp
+                    libxcomposite
+                    libxft
+                    libxinerama
+                    libxscrnsaver
+                    libxt
+                    mesa
+                    mit-krb5
+                    nspr
+                    nss-latest
+                    pango
+                    pciutils
+                    pipewire
+                    pixman
+                    pulseaudio
+                    speech-dispatcher
+                    sqlite
+                    startup-notification
+                    eudev
+                    unzip
+                    zip
+                    zlib))
+      (native-inputs (list alsa-lib
+                           autoconf-2.13
+                           `(,rust-librewolf "cargo")
+                           clang-18
+                           llvm-18
+                           m4
+                           nasm
+                           node-lts
+                           perl
+                           pkg-config
+                           python
+                           rust-librewolf
+                           rust-cbindgen-0.26
+                           which
+                           yasm))
+      (home-page "https://librewolf.net/")
+      (synopsis
+       "Custom version of Firefox, focused on privacy, security and freedom")
+      (description
+       "LibreWolf is designed to increase protection against tracking and
 fingerprinting techniques, while also including a few security improvements.
 This is achieved through our privacy and security oriented settings and
 patches.  LibreWolf also aims to remove all the telemetry, data collection and
 annoyances, as well as disabling anti-freedom features like DRM.")
-    (license license:mpl2.0)))
+      (license license:mpl2.0))))
