--- a/third_party/blink/public/public_features.gni
+++ b/third_party/blink/public/public_features.gni
@@ -4,6 +4,11 @@
 
 import("//build/config/ui.gni")
 
+declare_args() {
+  # Thorium internal flag
+  is_thorium_build = true
+}
+
 # Unhandled Tap enable means Contextual Search aka Touch to Search.
 # TODO(donnd): remove all unhandled-tap handling after the Long-press experiment
 #              is fully launched.
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -8928,12 +8928,6 @@
          "LauncherDynamicAnimations")},
 #endif  // BUILDFLAG(IS_CHROMEOS_ASH)
 
-#if BUILDFLAG(ENABLE_JXL_DECODER)
-    {"enable-jxl", flag_descriptions::kEnableJXLName,
-     flag_descriptions::kEnableJXLDescription, kOsAll,
-     FEATURE_VALUE_TYPE(blink::features::kJXL)},
-#endif  // BUILDFLAG(ENABLE_JXL_DECODER)
-
 #if BUILDFLAG(IS_ANDROID)
     {"incognito-reauthentication-for-android",
      flag_descriptions::kIncognitoReauthenticationForAndroidName,