--- a/modules/libpref/Preferences.cpp
+++ b/modules/libpref/Preferences.cpp
@@ -2339,33 +2339,34 @@ Preferences::HandleDirty()
 static nsresult
 openPrefFile(nsIFile* aFile);
 
 static const char kTelemetryPref[] = "toolkit.telemetry.enabled";
 static const char kChannelPref[] = "app.update.channel";
 
 // clang-format off
 static const char kPrefFileHeader[] =
-  "# Mozilla User Preferences"
+  "// Mozilla User Preferences"
   NS_LINEBREAK
   NS_LINEBREAK
-  "/* Do not edit this file."
+  "// DO NOT EDIT THIS FILE."
+  NS_LINEBREAK
+  "//"
   NS_LINEBREAK
-  " *"
+  "// If you make changes to this file while the application is running,"
   NS_LINEBREAK
-  " * If you make changes to this file while the application is running,"
+  "// the changes will be overwritten when the application exits."
   NS_LINEBREAK
-  " * the changes will be overwritten when the application exits."
+  "//"
   NS_LINEBREAK
-  " *"
+  "// To change a preference value, you can either: "
   NS_LINEBREAK
-  " * To make a manual change to preferences, you can visit the URL "
-  "about:config"
+  "// - Modify it via the UI (in the browser, this is via about:config); or"
   NS_LINEBREAK
-  " */"
+  "// - Set it within a user.js file in your profile."
   NS_LINEBREAK
   NS_LINEBREAK;
 // clang-format on
 
 // Note: if sShutdown is true, sPreferences will be nullptr.
 StaticRefPtr<Preferences> Preferences::sPreferences;
 bool Preferences::sShutdown = false;