pwa-builder
diff --git a/‎apps/pwabuilder/Frontend/package-lock.json‎
Lines changed: 0 additions & 1 deletion b/‎apps/pwabuilder/Frontend/package-lock.json‎
Lines changed: 0 additions & 1 deletion
diff --git a/‎apps/pwabuilder/Services/ManifestDetector.cs‎
Lines changed: 30 additions & 1 deletion b/‎apps/pwabuilder/Services/ManifestDetector.cs‎
Lines changed: 30 additions & 1 deletion
@@ -110,7 +110,8 @@ public ManifestDetector(WebStringCache webStringCache, IPuppeteerService puppete
             var manifestUrl = manifestUrls.LastOrDefault();
             if (manifestUrl == null)
             {
-                logger.LogWarning("Using Puppeteer to find manifest, no manifest links found in the page at {appUrl}.", appUrl);
+                var headContent = await TryGetHeadContentsFromPuppeteerAsync(puppeteerPage, logger);
+                logger.LogWarning("Using Puppeteer to find manifest, no manifest links found in the page at {appUrl}. Page <head> content: {pageContent}", appUrl, headContent);
                 return null;
             }
 
@@ -240,4 +241,32 @@ public ManifestDetector(WebStringCache webStringCache, IPuppeteerService puppete
             return null;
         }
     }
+
+    /// <summary>
+    /// Attempts to get the HTML contents of the head element from a Puppeteer page.
+    /// </summary>
+    /// <param name="page">The Puppeteer page to extract head contents from.</param>
+    /// <param name="logger">The logger to use for logging warnings.</param>
+    /// <returns>The HTML string of the head element, or null if it doesn't exist or an exception occurs.</returns>
+    private static async Task<string?> TryGetHeadContentsFromPuppeteerAsync(IPage page, ILogger logger)
+    {
+        try
+        {
+            var headContent = await page.EvaluateExpressionAsync<string?>("document.head?.outerHTML");
+
+            // Ensure head content is reasonable size (under 10k bytes) before returning
+            if (headContent is not null && System.Text.Encoding.UTF8.GetByteCount(headContent) > 10_000)
+            {
+                logger.LogWarning("Head content is too large ({size} bytes), truncating for logging.", System.Text.Encoding.UTF8.GetByteCount(headContent));
+                return headContent[..Math.Min(headContent.Length, 10_000)] + "... [truncated]";
+            }
+
+            return headContent;
+        }
+        catch (Exception error)
+        {
+            logger.LogWarning(error, "Error retrieving head contents from Puppeteer page.");
+            return null;
+        }
+    }
 }