diff --git a/browser/base/content/browser-init.js b/browser/base/content/browser-init.js
index 2456c5b4c6..826404b1b7 100644
--- a/browser/base/content/browser-init.js
+++ b/browser/base/content/browser-init.js
@@ -109,6 +109,22 @@ var gBrowserInit = {
     window.TabBarVisibility.update();
     TabsInTitlebar.init();
 
+    // If a list of languages were passed, use them.
+    let camouLocale = ChromeUtils.camouGetString("locale:all")
+      || ChromeUtils.camouGetString("navigator.language");
+    // If locale:all was NOT passed, but locale:language and locale:region was,
+    // fall back to it instead.
+    if (!camouLocale) {
+      let language = ChromeUtils.camouGetString("locale:language");
+      let region = ChromeUtils.camouGetString("locale:region");
+      if (language && region) {
+        camouLocale = language + "-" + region + ", " + language;
+      }
+    }
+    // Set the locale if it was found.
+    if (camouLocale)
+      Services.prefs.setCharPref("intl.accept_languages", camouLocale);
+
     new LightweightThemeConsumer(document);
 
     if (
diff --git a/intl/components/src/Locale.cpp b/intl/components/src/Locale.cpp
index 9a043518cf..a8d3733212 100644
--- a/intl/components/src/Locale.cpp
+++ b/intl/components/src/Locale.cpp
@@ -24,11 +24,56 @@
 
 #include "unicode/uloc.h"
 #include "unicode/utypes.h"
+#include "MaskConfig.hpp"
 
 namespace mozilla::intl {
 
 using namespace intl::LanguageTagLimits;
 
+
+// Helper methods for header file
+
+const char* Locale::GetCamouLanguage() {
+  if (auto lang = MaskConfig::GetString("locale:language"))
+    return lang.value().c_str();
+  return nullptr;
+}
+
+const char* Locale::GetCamouRegion() {
+  if (auto region = MaskConfig::GetString("locale:region"))
+    return region.value().c_str();
+  return nullptr;
+}
+
+const char* Locale::GetCamouScript() {
+  if (auto script = MaskConfig::GetString("locale:script"))
+    return script.value().c_str();
+  return nullptr;
+}
+
+// Publicly exposed methods
+
+const char* Locale::GetCamouLocale() {
+  static std::string locale;
+
+  if (auto lang = MaskConfig::GetString("locale:language"))
+    if (auto region = MaskConfig::GetString("locale:region"))
+      locale = (lang.value() + "-" + region.value());
+  if (auto value = MaskConfig::GetString("navigator.language"))
+    locale = value.value();
+  if (locale.empty())
+    return nullptr;
+  return locale.c_str();
+}
+
+const char* Locale::GetDefaultLocale() {
+  // In Omegafox, GetDefaultLocale is defined outside the header
+  // to access MaskConfig.
+  if (auto value = GetCamouLocale())
+    return value;
+  return uloc_getDefault();
+}
+
 template <typename CharT>
 bool IsStructurallyValidLanguageTag(Span<const CharT> aLanguage) {
   // unicode_language_subtag = alpha{2,3} | alpha{5,8};
diff --git a/intl/components/src/Locale.h b/intl/components/src/Locale.h
index 1f4e06f543..448486a479 100644
--- a/intl/components/src/Locale.h
+++ b/intl/components/src/Locale.h
@@ -190,8 +190,11 @@ using UniqueChars = UniquePtr<char[]>;
  */
 class MOZ_STACK_CLASS Locale final {
   LanguageSubtag mLanguage = {};
+  mutable LanguageSubtag mCamouLanguage = {};
   ScriptSubtag mScript = {};
+  mutable ScriptSubtag mCamouScript = {};
   RegionSubtag mRegion = {};
+  mutable RegionSubtag mCamouRegion = {};
 
   using VariantsVector = Vector<UniqueChars, 2>;
   using ExtensionsVector = Vector<UniqueChars, 2>;
@@ -314,9 +317,28 @@ class MOZ_STACK_CLASS Locale final {
     }
   };
 
-  const LanguageSubtag& Language() const { return mLanguage; }
-  const ScriptSubtag& Script() const { return mScript; }
-  const RegionSubtag& Region() const { return mRegion; }
+  const LanguageSubtag& Language() const {
+    if (const char* lang = GetCamouLanguage()) {
+      mCamouLanguage.Set(mozilla::Span<const char>(lang, strlen(lang)));
+      return mCamouLanguage;
+    }
+    return mLanguage;
+  }
+  const ScriptSubtag& Script() const {
+    if (const char* script = GetCamouScript()) {
+      mCamouScript.Set(mozilla::Span<const char>(script, strlen(script)));
+      return mCamouScript;
+    }
+    return mScript;
+  }
+  const RegionSubtag& Region() const {
+    if (const char* region = GetCamouRegion()) {
+      mCamouRegion.Set(mozilla::Span<const char>(region, strlen(region)));
+      return mCamouRegion;
+    }
+    return mRegion;
+  }
+  
   auto Variants() const { return SubtagEnumeration(mVariants); }
   auto Extensions() const { return SubtagEnumeration(mExtensions); }
   Maybe<Span<const char>> PrivateUse() const {
@@ -483,7 +505,15 @@ class MOZ_STACK_CLASS Locale final {
    *
    * Also see <https://unicode-org.github.io/icu/userguide/locale>.
    */
-  static const char* GetDefaultLocale() { return uloc_getDefault(); }
+  static const char* GetDefaultLocale();
+
+  static const char* GetCamouLocale();
+
+  static const char* GetCamouLanguage();
+
+  static const char* GetCamouRegion();
+
+  static const char* GetCamouScript();
 
   /**
    * Returns an iterator over all supported locales.
diff --git a/intl/locale/OSPreferences.cpp b/intl/locale/OSPreferences.cpp
index b87924b61a..2eaa960c04 100644
--- a/intl/locale/OSPreferences.cpp
+++ b/intl/locale/OSPreferences.cpp
@@ -406,6 +406,10 @@ bool OSPreferences::GetDateTimeConnectorPattern(const nsACString& aLocale,
  */
 NS_IMETHODIMP
 OSPreferences::GetSystemLocales(nsTArray<nsCString>& aRetVal) {
+  if (const char* camouLocale = mozilla::intl::Locale::GetCamouLocale()) {
+    aRetVal.AppendElement(camouLocale);
+    return NS_OK;
+  }
   if (!mSystemLocales.IsEmpty()) {
     aRetVal = mSystemLocales.Clone();
     return NS_OK;
@@ -425,7 +429,10 @@ OSPreferences::GetSystemLocales(nsTArray<nsCString>& aRetVal) {
 
 NS_IMETHODIMP
 OSPreferences::GetSystemLocale(nsACString& aRetVal) {
-  if (!mSystemLocales.IsEmpty()) {
+  if (const char* camouLocale = mozilla::intl::Locale::GetCamouLocale()) {
+    aRetVal = camouLocale;
+    return NS_OK;
+  } else if (!mSystemLocales.IsEmpty()) {
     aRetVal = mSystemLocales[0];
   } else {
     AutoTArray<nsCString, 10> locales;
@@ -439,6 +446,10 @@ OSPreferences::GetSystemLocale(nsACString& aRetVal) {
 
 NS_IMETHODIMP
 OSPreferences::GetRegionalPrefsLocales(nsTArray<nsCString>& aRetVal) {
+  if (const char* camouLocale = mozilla::intl::Locale::GetCamouLocale()) {
+    aRetVal.AppendElement(camouLocale);
+    return NS_OK;
+  }
   if (!mRegionalPrefsLocales.IsEmpty()) {
     aRetVal = mRegionalPrefsLocales.Clone();
     return NS_OK;