- Patch #275092 by kbahey, greggles and Arancaytar: emit X-Generator and meta-generator tags.

modules/system/system.module

@@ -146,6 +146,12 @@ function system_theme() {
     'system_powered_by' => array(
       'arguments' => array('image_path' => NULL),
     ),
+    'meta_generator_html' => array(
+      'arguments' => array('version' => NULL),
+    ),
+    'meta_generator_header' => array(
+      'arguments' => array('version' => NULL),
+    ),
     'system_compact_link' => array(),
   ));
 }
@@ -682,6 +688,15 @@ function system_init() {
   drupal_add_css(drupal_get_path('module', 'system') . '/defaults.css', 'module');
   drupal_add_css(drupal_get_path('module', 'system') . '/system.css', 'module');
   drupal_add_css(drupal_get_path('module', 'system') . '/system-menus.css', 'module');
+
+  // Get the major version
+  list($version,) = explode('.', VERSION);
+
+  // Emit the META tag in the HTML HEAD section
+  theme('meta_generator_html', $version);
+
+  // Emit the HTTP Header too
+  theme('meta_generator_header', $version);
 }
 
 /**
@@ -2071,3 +2086,22 @@ function theme_system_compact_link() {
 
   return $output;
 }
+
+
+/**
+ * Send Drupal and the major version number in the META GENERATOR HTML.
+ *
+ * @ingroup themeable
+ */
+function theme_meta_generator_html($version = VERSION) {
+  drupal_set_html_head('<meta name="Generator" content="Drupal ' . $version . ' (http://drupal.org)" />');
+}
+
+/**
+ * Send Drupal and the major version number in the HTTP headers.
+ *
+ * @ingroup themeable
+ */
+function theme_meta_generator_header($version = VERSION) {
+  drupal_set_header('X-Generator: Drupal ' . $version . ' (http://drupal.org)');
+}