From c7e4c94bb648f24adfc435875459034984d0d729 Mon Sep 17 00:00:00 2001
From: Andreas Svanberg <andreas.svanberg@mensa.se>
Date: Thu, 14 May 2026 09:41:16 +0200
Subject: [PATCH] Make <wicket:header-items/> HTML spec compliant

According to the [HTML specification for `<meta>` element](https://html.spec.whatwg.org/multipage/semantics.html#the-meta-element), a `<meta>` tag with the `name` attribute specified must also specify `content`.

> If either name, http-equiv, or itemprop is specified, then the content attribute must also be specified. Otherwise, it must be omitted.

Since `<wicket:header-items/>` is often placed in a base class for pages it means that no pages in the application will pass HTML validation.
---
 .../wicket/markup/html/internal/HtmlHeaderItemsContainer.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wicket-core/src/main/java/org/apache/wicket/markup/html/internal/HtmlHeaderItemsContainer.java b/wicket-core/src/main/java/org/apache/wicket/markup/html/internal/HtmlHeaderItemsContainer.java
index 4249c6a2b18..d6758cd7126 100644
--- a/wicket-core/src/main/java/org/apache/wicket/markup/html/internal/HtmlHeaderItemsContainer.java
+++ b/wicket-core/src/main/java/org/apache/wicket/markup/html/internal/HtmlHeaderItemsContainer.java
@@ -44,7 +44,7 @@ public HtmlHeaderItemsContainer(String id)
 	protected void onAfterRender() {
 		super.onAfterRender();
 		final Response webResponse = getResponse();
-		webResponse.write("<meta name=\"wicket.header.items\"/>");
+		webResponse.write("<meta name=\"wicket.header.items\" content=\"\"/>");
 	}
 
 	@Override