diff --git a/admin/settings/development.php b/admin/settings/development.php
index 88d6df729c37e..207296a792af5 100644
--- a/admin/settings/development.php
+++ b/admin/settings/development.php
@@ -51,6 +51,7 @@
              100 => new lang_string('debugsqltrace100', 'admin'))));
     $temp->add(new admin_setting_configcheckbox('debugvalidators', new lang_string('debugvalidators', 'admin'), new lang_string('configdebugvalidators', 'admin'), 0));
     $temp->add(new admin_setting_configcheckbox('debugpageinfo', new lang_string('debugpageinfo', 'admin'), new lang_string('configdebugpageinfo', 'admin'), 0));
+    $temp->add(new admin_setting_configcheckbox('debugtemplateinfo', new lang_string('debugtemplateinfo', 'admin'), new lang_string('debugtemplateinfo_desc', 'admin'), 0));
     $ADMIN->add('development', $temp);
 
     // "Profiling" settingpage (conditionally if the 'xhprof' extension is available only).
diff --git a/lang/en/admin.php b/lang/en/admin.php
index bc34156ec17b7..7e8e79f63e0f7 100644
--- a/lang/en/admin.php
+++ b/lang/en/admin.php
@@ -483,6 +483,8 @@
 $string['debugsqltrace_desc'] = 'If enabled, a partial or full PHP stack trace is added into the SQL as a comment.';
 $string['debugstringids'] = 'Show origin of languages strings';
 $string['debugstringids_desc'] = 'If enabled, language string components and identifiers are displayed when ?strings=1 or &strings=1 is appended to the page URL.';
+$string['debugtemplateinfo'] = 'Show template information';
+$string['debugtemplateinfo_desc'] = 'If enabled, templates used for rendering are shown as comments in the page HTML. Use for temporary debugging only, as it produces HTML validation errors and could break some page scripts.';
 $string['debugvalidators'] = 'Show validator links';
 $string['defaultcity'] = 'Default city';
 $string['defaultcity_help'] = 'A city entered here will be the default city when creating new user accounts.';
diff --git a/lib/classes/output/mustache_filesystem_loader.php b/lib/classes/output/mustache_filesystem_loader.php
index e79b479fed500..6c1e1603cab26 100644
--- a/lib/classes/output/mustache_filesystem_loader.php
+++ b/lib/classes/output/mustache_filesystem_loader.php
@@ -65,4 +65,19 @@ protected function getFileName($name) {
     protected function shouldCheckPath() {
         return true;
     }
+
+    /**
+     * Load a Template by name.
+     *
+     * @param string $name the template name
+     * @return string Mustache Template source
+     */
+    public function load($name): string {
+        global $CFG;
+        if (!empty($CFG->debugtemplateinfo)) {
+            // We use many templates per page. We don't want to allocate more memory than necessary.
+            return "<!-- template(PHP): $name -->" . parent::load($name) . "<!-- /template(PHP): $name -->";
+        }
+        return parent::load($name);
+    }
 }
diff --git a/lib/classes/output/mustache_template_source_loader.php b/lib/classes/output/mustache_template_source_loader.php
index 39d6bd8ebc315..471bc0c6feb3b 100644
--- a/lib/classes/output/mustache_template_source_loader.php
+++ b/lib/classes/output/mustache_template_source_loader.php
@@ -88,6 +88,7 @@ public function load(
         string $themename,
         bool $includecomments = false
     ) : string {
+        global $CFG;
         // Get the template source from the callback.
         $source = ($this->gettemplatesource)($component, $name, $themename);
 
@@ -95,7 +96,9 @@ public function load(
         if (!$includecomments) {
             $source = $this->strip_template_comments($source);
         }
-
+        if (!empty($CFG->debugtemplateinfo)) {
+            return "<!-- template(JS): $name -->" . $source . "<!-- /template(JS): $name -->";
+        }
         return $source;
     }