diff --git a/packages/rum-legacy/verification/index.html b/packages/rum-legacy/verification/index.html
index 2bf32b7f4a..1e0bb47740 100644
--- a/packages/rum-legacy/verification/index.html
+++ b/packages/rum-legacy/verification/index.html
@@ -172,7 +172,14 @@ <h1>RUM legacy build verification</h1>
       function showEnvironment() {
         var mode =
           typeof document.documentMode === 'undefined' ? '(none - documentMode needs IE8+, or not Trident at all)' : document.documentMode
+        /* The protocol decides two results on this page and neither failure names it: over file://
+           the browser refuses to write the session cookie, and there is no origin to send a
+           same-origin request to. Both then read as a broken SDK. */
+        var protocol = window.location.protocol
+        var protocolNote =
+          protocol === 'file:' ? 'file: (serve this page over http(s) - see the notes below)' : protocol
         var pairs = [
+          ['location.protocol', protocolNote],
           ['document.documentMode', String(mode)],
           ['navigator.userAgent', navigator.userAgent],
           [
@@ -290,7 +297,12 @@ <h1>RUM legacy build verification</h1>
           loadBundle(function (loaded) {
             if (!loaded || !window.FC_RUM) {
               record('The bundle parses and loads', 'fail', 'window.FC_RUM is ' + typeof window.FC_RUM)
-              note('Stopped: nothing else can be checked while the script does not load.')
+              note(
+                'Stopped: fc-rum-legacy.js did not load. It has to be served from the same ' +
+                  'directory as this page. This repository does not carry the built bundle - run ' +
+                  'the package build, then open this page through scripts/verification-server.js, ' +
+                  'which serves the two together.'
+              )
               return
             }
             record('The bundle parses and loads', 'pass', 'FC_RUM.version = ' + window.FC_RUM.version)