From 81ec7c6cd471c17ae1387e18876f0baa78dc4dfd Mon Sep 17 00:00:00 2001
From: Marcos Caceres <caceres_m@apple.com>
Date: Sat, 9 May 2026 12:59:09 +1000
Subject: [PATCH] fix(core/issues-notes): warn about githubusercontent images
 in issues

GitHub issue bodies often contain images hosted on
user-images.githubusercontent.com. These URLs are rejected by
W3C publication tools (pubrules). Warn spec authors so they can
download and self-host the images.

Closes #3825
---
 src/core/issues-notes.js | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/core/issues-notes.js b/src/core/issues-notes.js
index d7b238d59d..36ad331f1a 100644
--- a/src/core/issues-notes.js
+++ b/src/core/issues-notes.js
@@ -190,6 +190,15 @@ function handleIssues(ins, ghIssues, conf) {
         body = document
           .createRange()
           .createContextualFragment(ghIssue.bodyHTML);
+        const externalImages = /** @type {NodeListOf<HTMLImageElement>} */ (
+          body.querySelectorAll("img[src*='githubusercontent.com']")
+        );
+        if (externalImages.length) {
+          const msg = `Issue #${dataNum} contains images hosted on githubusercontent.com which may be rejected by W3C publication tools.`;
+          const hint =
+            "Download the images and host them alongside the spec source.";
+          showWarning(msg, name, { hint });
+        }
       }
       div.append(titleParent, body);
     }