diff --git a/core/templates/external-js/save-all-external-js.tid b/core/templates/external-js/save-all-external-js.tid
index a41cc0682..cd15cedc3 100644
--- a/core/templates/external-js/save-all-external-js.tid
+++ b/core/templates/external-js/save-all-external-js.tid
@@ -4,5 +4,7 @@ title: $:/core/save/all-external-js
 \define saveTiddlerFilter()
 [is[tiddler]] -[prefix[$:/state/popup/]] -[prefix[$:/temp/]] -[prefix[$:/HistoryList]] -[status[pending]plugin-type[import]] -[[$:/core]] -[[$:/boot/boot.css]] -[type[application/javascript]library[yes]] -[[$:/boot/boot.js]] -[[$:/boot/bootprefix.js]] +[sort[title]] $(publishFilter)$
 \end
-\define coreURL() %24%3A%2Fcore%2Ftemplates%2Ftiddlywiki5.js
-{{$:/core/templates/tiddlywiki5-external-js.html}}
+\define defaultCoreURL() %24%3A%2Fcore%2Ftemplates%2Ftiddlywiki5.js
+<$let coreURL={{{ [[coreURL]is[variable]then<coreURL>else<defaultCoreURL>] }}}>
+	{{$:/core/templates/tiddlywiki5-external-js.html}}
+</$let>
diff --git a/core/templates/external-js/save-offline-external-js.tid b/core/templates/external-js/save-offline-external-js.tid
index 7175f7eea..2dfca5d52 100644
--- a/core/templates/external-js/save-offline-external-js.tid
+++ b/core/templates/external-js/save-offline-external-js.tid
@@ -4,5 +4,7 @@ title: $:/core/save/offline-external-js
 \define saveTiddlerFilter()
 [is[tiddler]] -[prefix[$:/state/popup/]] -[prefix[$:/temp/]] -[prefix[$:/HistoryList]] -[status[pending]plugin-type[import]] -[[$:/core]] -[[$:/plugins/tiddlywiki/filesystem]] -[[$:/plugins/tiddlywiki/tiddlyweb]] -[[$:/boot/boot.css]] -[type[application/javascript]library[yes]] -[[$:/boot/boot.js]] -[[$:/boot/bootprefix.js]] +[sort[title]] $(publishFilter)$
 \end
-\define coreURL() tiddlywikicore-$(version)$.js
-{{$:/core/templates/tiddlywiki5-external-js.html}}
+\define defaultCoreURL() tiddlywikicore-$(version)$.js
+<$let coreURL={{{ [[coreURL]is[variable]then<coreURL>else<defaultCoreURL>] }}}>
+	{{$:/core/templates/tiddlywiki5-external-js.html}}
+</$let>