--- a/modules/libpref/init/StaticPrefList.h
+++ b/modules/libpref/init/StaticPrefList.h
@@ -898,12 +898,22 @@ VARCACHE_PREF(
 
 //---------------------------------------------------------------------------
 // Preferences prefs
 //---------------------------------------------------------------------------
 
 PREF("preferences.allow.omt-write", bool, true)
 
 //---------------------------------------------------------------------------
+// View source prefs
+//---------------------------------------------------------------------------
+
+VARCACHE_PREF(
+  "view_source.editor.external",
+   view_source_editor_external,
+  bool, false
+)
+
+//---------------------------------------------------------------------------
 // End of prefs
 //---------------------------------------------------------------------------
 
 // clang-format on

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1066,17 +1066,16 @@ pref("devtools.gcli.imgurClientID", '0df
 pref("devtools.gcli.imgurUploadURL", "https://api.imgur.com/3/image");
 
 // GCLI commands directory
 pref("devtools.commands.dir", "");
 
 // view source
 pref("view_source.syntax_highlight", true);
 pref("view_source.wrap_long_lines", false);
-pref("view_source.editor.external", false);
 pref("view_source.editor.path", "");
 // allows to add further arguments to the editor; use the %LINE% placeholder
 // for jumping to a specific line (e.g. "/line:%LINE%" or "--goto %LINE%")
 pref("view_source.editor.args", "");
 
 // When true this will word-wrap plain text documents.
 pref("plain_text.wrap_long_lines", false);
 

--- a/parser/html/nsHtml5TreeOpExecutor.cpp
+++ b/parser/html/nsHtml5TreeOpExecutor.cpp
@@ -8,16 +8,17 @@
 #include "mozilla/Likely.h"
 #include "mozilla/dom/ScriptLoader.h"
 #include "mozilla/dom/nsCSPService.h"
 
 #include "GeckoProfiler.h"
 #include "mozAutoDocUpdate.h"
 #include "mozilla/IdleTaskRunner.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs.h"
 #include "mozilla/css/Loader.h"
 #include "nsContentUtils.h"
 #include "nsError.h"
 #include "nsHtml5AutoPauseUpdate.h"
 #include "nsHtml5Parser.h"
 #include "nsHtml5StreamParser.h"
 #include "nsHtml5Tokenizer.h"
 #include "nsHtml5TreeBuilder.h"
@@ -917,28 +918,20 @@ nsHtml5TreeOpExecutor::GetViewSourceBase
       // Fail gracefully if the base URL isn't a view-source: URL.
       // Not sure if this can ever happen.
       mViewSourceBaseURI = orig;
     }
   }
   return mViewSourceBaseURI;
 }
 
-// static
-void
-nsHtml5TreeOpExecutor::InitializeStatics()
-{
-  mozilla::Preferences::AddBoolVarCache(&sExternalViewSource,
-                                        "view_source.editor.external");
-}
-
 bool
 nsHtml5TreeOpExecutor::IsExternalViewSource()
 {
-  if (!sExternalViewSource) {
+  if (!StaticPrefs::view_source_editor_external()) {
     return false;
   }
   bool isViewSource = false;
   if (mDocumentURI) {
     mDocumentURI->SchemeIs("view-source", &isViewSource);
   }
   return isViewSource;
 }
@@ -1187,9 +1180,8 @@ nsHtml5TreeOpExecutor::SetSpeculationRef
 
 #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
 uint32_t nsHtml5TreeOpExecutor::sAppendBatchMaxSize = 0;
 uint32_t nsHtml5TreeOpExecutor::sAppendBatchSlotsExamined = 0;
 uint32_t nsHtml5TreeOpExecutor::sAppendBatchExaminations = 0;
 uint32_t nsHtml5TreeOpExecutor::sLongestTimeOffTheEventLoop = 0;
 uint32_t nsHtml5TreeOpExecutor::sTimesFlushLoopInterrupted = 0;
 #endif
-bool nsHtml5TreeOpExecutor::sExternalViewSource = false;

--- a/parser/html/nsHtml5TreeOpExecutor.h
+++ b/parser/html/nsHtml5TreeOpExecutor.h
@@ -40,17 +40,16 @@ class nsHtml5TreeOpExecutor final
   using Encoding = mozilla::Encoding;
   template<typename T>
   using NotNull = mozilla::NotNull<T>;
 
 public:
   NS_DECL_ISUPPORTS_INHERITED
 
 private:
-  static bool sExternalViewSource;
 #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
   static uint32_t sAppendBatchMaxSize;
   static uint32_t sAppendBatchSlotsExamined;
   static uint32_t sAppendBatchExaminations;
   static uint32_t sLongestTimeOffTheEventLoop;
   static uint32_t sTimesFlushLoopInterrupted;
 #endif
 
@@ -262,18 +261,16 @@ public:
 
   void SetSpeculationReferrerPolicy(ReferrerPolicy aReferrerPolicy);
   void SetSpeculationReferrerPolicy(const nsAString& aReferrerPolicy);
 
   void AddSpeculationCSP(const nsAString& aCSP);
 
   void AddBase(const nsAString& aURL);
 
-  static void InitializeStatics();
-
 private:
   nsHtml5Parser* GetParser();
 
   bool IsExternalViewSource();
 
   /**
    * Get a nsIURI for an nsString if the URL hasn't been preloaded yet.
    */