Link to the deprecation URL, not the plugin URL

core/src/main/java/hudson/PluginManager.java

@@ -145,6 +145,7 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Future;
+import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
@@ -2257,10 +2258,10 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
             return !getDeprecatedPlugins().isEmpty();
         }
 
-        public List<PluginWrapper> getDeprecatedPlugins() {
+        public Map<PluginWrapper, String> getDeprecatedPlugins() {
             return Jenkins.get().getPluginManager().getPlugins().stream()
                     .filter(PluginWrapper::isDeprecated)
-                    .collect(Collectors.toList());
+                    .collect(Collectors.toMap(Function.identity(), it -> it.getDeprecations().get(0).url));
         }
     }
 

core/src/main/resources/hudson/PluginManager/PluginDeprecationMonitor/message.jelly

@@ -27,15 +27,8 @@ THE SOFTWARE.
   <div class="alert alert-warning">
     <dl>
       <dt>${%DeprecatedPlugins}</dt>
-      <j:forEach var="p" items="${it.getDeprecatedPlugins()}">
-        <j:choose>
-          <j:when test="${p.url != null and p.url.matches('(?i)^https?.+$')}">
-            <dd><a href="${p.url}" target="_blank">${p.displayName}</a></dd>
-          </j:when>
-          <j:otherwise>
-            <dd>${p.displayName}}</dd>
-          </j:otherwise>
-        </j:choose>
+      <j:forEach var="e" items="${it.getDeprecatedPlugins()}">
+        <dd><a href="${e.value}" target="_blank">${e.key.displayName}</a></dd>
       </j:forEach>
     </dl>
     <p>${%DeprecatedPluginsDescription}</p>