Merge "Improve documentation of $wgReferrerPolicy"

diff --combined includes/DefaultSettings.php
index b707174,d0a02de..fecf322
--- 1/includes/DefaultSettings.php
--- 2/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@@ -316,10 -316,16 +316,16 @@@ $wgAppleTouchIcon = false
  
  /**
   * Value for the referrer policy meta tag.
-  * One of 'never', 'default', 'origin', 'always'. Setting it to false just
-  * prevents the meta tag from being output.
-  * See https://www.w3.org/TR/referrer-policy/ for details.
-  *
+  * One of the values defined in the Referrer Policy specification:
+  * https://w3c.github.io/webappsec-referrer-policy/
+  * ('no-referrer', 'no-referrer-when-downgrade', 'same-origin',
+  * 'origin', 'strict-origin', 'origin-when-cross-origin',
+  * 'strict-origin-when-cross-origin', or 'unsafe-url')
+  * Setting it to false prevents the meta tag from being output
+  * (which results in falling back to the Referrer-Policy header,
+  * or 'no-referrer-when-downgrade' if that's not set either.)
+  *
+  * @var string|bool
   * @since 1.25
   */
  $wgReferrerPolicy = false;
@@@ -3763,7 -3769,7 +3769,7 @@@ $wgResourceLoaderValidateStaticJS = fal
   * @code
   *   $wgResourceLoaderLESSVars = [
   *     'exampleFontSize'  => '1em',
 - *     'exampleBlue' => '#eee',
 + *     'exampleBlue' => '#36c',
   *   ];
   * @endcode
   * @since 1.22
@@@ -6953,7 -6959,6 +6959,7 @@@ $wgUseTagFilter = true
   * - 'mw-blank': Edit completely blanks the page
   * - 'mw-replace': Edit removes more than 90% of the content
   * - 'mw-rollback': Edit is a rollback, made through the rollback link or rollback API
 + * - 'mw-undo': Edit made through an undo link
   *
   * @var array
   * @since 1.31
@@@ -6965,8 -6970,7 +6971,8 @@@ $wgSoftwareTags = 
        'mw-changed-redirect-target' => true,
        'mw-blank' => true,
        'mw-replace' => true,
 -      'mw-rollback' => true
 +      'mw-rollback' => true,
 +      'mw-undo' => true,
  ];
  
  /**