diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-includes/IXR/class-IXR-error.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/IXR/class-IXR-error.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * IXR_Error
+ *
+ * @package IXR
+ * @since 1.5.0
+ */
+class IXR_Error
+{
+    var $code;
+    var $message;
+
+	/**
+	 * PHP5 constructor.
+	 */
+    function __construct( $code, $message )
+    {
+        $this->code = $code;
+        $this->message = htmlspecialchars($message);
+    }
+
+	/**
+	 * PHP4 constructor.
+	 */
+	public function IXR_Error( $code, $message ) {
+		self::__construct( $code, $message );
+	}
+
+    function getXml()
+    {
+        $xml = <<<EOD
+<methodResponse>
+  <fault>
+    <value>
+      <struct>
+        <member>
+          <name>faultCode</name>
+          <value><int>{$this->code}</int></value>
+        </member>
+        <member>
+          <name>faultString</name>
+          <value><string>{$this->message}</string></value>
+        </member>
+      </struct>
+    </value>
+  </fault>
+</methodResponse>
+
+EOD;
+        return $xml;
+    }
+}