diff -r c7c34916027a -r 177826044cd9 wp/wp-admin/admin-ajax.php
--- a/wp/wp-admin/admin-ajax.php	Mon Oct 14 18:06:33 2019 +0200
+++ b/wp/wp-admin/admin-ajax.php	Mon Oct 14 18:28:13 2019 +0200
@@ -25,8 +25,9 @@
 send_origin_headers();
 
 // Require an action parameter
-if ( empty( $_REQUEST['action'] ) )
+if ( empty( $_REQUEST['action'] ) ) {
 	wp_die( '0', 400 );
+}
 
 /** Load WordPress Administration APIs */
 require_once( ABSPATH . 'wp-admin/includes/admin.php' );
@@ -44,75 +45,147 @@
 do_action( 'admin_init' );
 
 $core_actions_get = array(
-	'fetch-list', 'ajax-tag-search', 'wp-compression-test', 'imgedit-preview', 'oembed-cache',
-	'autocomplete-user', 'dashboard-widgets', 'logged-in',
+	'fetch-list',
+	'ajax-tag-search',
+	'wp-compression-test',
+	'imgedit-preview',
+	'oembed-cache',
+	'autocomplete-user',
+	'dashboard-widgets',
+	'logged-in',
 );
 
 $core_actions_post = array(
-	'oembed-cache', 'image-editor', 'delete-comment', 'delete-tag', 'delete-link',
-	'delete-meta', 'delete-post', 'trash-post', 'untrash-post', 'delete-page', 'dim-comment',
-	'add-link-category', 'add-tag', 'get-tagcloud', 'get-comments', 'replyto-comment',
-	'edit-comment', 'add-menu-item', 'add-meta', 'add-user', 'closed-postboxes',
-	'hidden-columns', 'update-welcome-panel', 'menu-get-metabox', 'wp-link-ajax',
-	'menu-locations-save', 'menu-quick-search', 'meta-box-order', 'get-permalink',
-	'sample-permalink', 'inline-save', 'inline-save-tax', 'find_posts', 'widgets-order',
-	'save-widget', 'delete-inactive-widgets', 'set-post-thumbnail', 'date_format', 'time_format',
-	'wp-remove-post-lock', 'dismiss-wp-pointer', 'upload-attachment', 'get-attachment',
-	'query-attachments', 'save-attachment', 'save-attachment-compat', 'send-link-to-editor',
-	'send-attachment-to-editor', 'save-attachment-order', 'heartbeat', 'get-revision-diffs',
-	'save-user-color-scheme', 'update-widget', 'query-themes', 'parse-embed', 'set-attachment-thumbnail',
-	'parse-media-shortcode', 'destroy-sessions', 'install-plugin', 'update-plugin', 'crop-image',
-	'generate-password', 'save-wporg-username', 'delete-plugin', 'search-plugins',
-	'search-install-plugins', 'activate-plugin', 'update-theme', 'delete-theme', 'install-theme',
-	'get-post-thumbnail-html', 'get-community-events', 'edit-theme-plugin-file',
+	'oembed-cache',
+	'image-editor',
+	'delete-comment',
+	'delete-tag',
+	'delete-link',
+	'delete-meta',
+	'delete-post',
+	'trash-post',
+	'untrash-post',
+	'delete-page',
+	'dim-comment',
+	'add-link-category',
+	'add-tag',
+	'get-tagcloud',
+	'get-comments',
+	'replyto-comment',
+	'edit-comment',
+	'add-menu-item',
+	'add-meta',
+	'add-user',
+	'closed-postboxes',
+	'hidden-columns',
+	'update-welcome-panel',
+	'menu-get-metabox',
+	'wp-link-ajax',
+	'menu-locations-save',
+	'menu-quick-search',
+	'meta-box-order',
+	'get-permalink',
+	'sample-permalink',
+	'inline-save',
+	'inline-save-tax',
+	'find_posts',
+	'widgets-order',
+	'save-widget',
+	'delete-inactive-widgets',
+	'set-post-thumbnail',
+	'date_format',
+	'time_format',
+	'wp-remove-post-lock',
+	'dismiss-wp-pointer',
+	'upload-attachment',
+	'get-attachment',
+	'query-attachments',
+	'save-attachment',
+	'save-attachment-compat',
+	'send-link-to-editor',
+	'send-attachment-to-editor',
+	'save-attachment-order',
+	'heartbeat',
+	'get-revision-diffs',
+	'save-user-color-scheme',
+	'update-widget',
+	'query-themes',
+	'parse-embed',
+	'set-attachment-thumbnail',
+	'parse-media-shortcode',
+	'destroy-sessions',
+	'install-plugin',
+	'update-plugin',
+	'crop-image',
+	'generate-password',
+	'save-wporg-username',
+	'delete-plugin',
+	'search-plugins',
+	'search-install-plugins',
+	'activate-plugin',
+	'update-theme',
+	'delete-theme',
+	'install-theme',
+	'get-post-thumbnail-html',
+	'get-community-events',
+	'edit-theme-plugin-file',
 	'wp-privacy-export-personal-data',
 	'wp-privacy-erase-personal-data',
-	'update-try-gutenberg-panel',
+	'health-check-site-status-result',
+	'health-check-dotorg-communication',
+	'health-check-is-in-debug-mode',
+	'health-check-background-updates',
+	'health-check-loopback-requests',
+	'health-check-get-sizes',
 );
 
 // Deprecated
 $core_actions_post_deprecated = array( 'wp-fullscreen-save-post', 'press-this-save-post', 'press-this-add-category' );
-$core_actions_post = array_merge( $core_actions_post, $core_actions_post_deprecated );
+$core_actions_post            = array_merge( $core_actions_post, $core_actions_post_deprecated );
 
 // Register core Ajax calls.
-if ( ! empty( $_GET['action'] ) && in_array( $_GET['action'], $core_actions_get ) )
+if ( ! empty( $_GET['action'] ) && in_array( $_GET['action'], $core_actions_get ) ) {
 	add_action( 'wp_ajax_' . $_GET['action'], 'wp_ajax_' . str_replace( '-', '_', $_GET['action'] ), 1 );
+}
 
-if ( ! empty( $_POST['action'] ) && in_array( $_POST['action'], $core_actions_post ) )
+if ( ! empty( $_POST['action'] ) && in_array( $_POST['action'], $core_actions_post ) ) {
 	add_action( 'wp_ajax_' . $_POST['action'], 'wp_ajax_' . str_replace( '-', '_', $_POST['action'] ), 1 );
+}
 
 add_action( 'wp_ajax_nopriv_heartbeat', 'wp_ajax_nopriv_heartbeat', 1 );
 
+$action = ( isset( $_REQUEST['action'] ) ) ? $_REQUEST['action'] : '';
+
 if ( is_user_logged_in() ) {
 	// If no action is registered, return a Bad Request response.
-	if ( ! has_action( 'wp_ajax_' . $_REQUEST['action'] ) ) {
+	if ( ! has_action( "wp_ajax_{$action}" ) ) {
 		wp_die( '0', 400 );
 	}
 
 	/**
 	 * Fires authenticated Ajax actions for logged-in users.
 	 *
-	 * The dynamic portion of the hook name, `$_REQUEST['action']`,
-	 * refers to the name of the Ajax action callback being fired.
+	 * The dynamic portion of the hook name, `$action`, refers
+	 * to the name of the Ajax action callback being fired.
 	 *
 	 * @since 2.1.0
 	 */
-	do_action( 'wp_ajax_' . $_REQUEST['action'] );
+	do_action( "wp_ajax_{$action}" );
 } else {
 	// If no action is registered, return a Bad Request response.
-	if ( ! has_action( 'wp_ajax_nopriv_' . $_REQUEST['action'] ) ) {
+	if ( ! has_action( "wp_ajax_nopriv_{$action}" ) ) {
 		wp_die( '0', 400 );
 	}
 
 	/**
 	 * Fires non-authenticated Ajax actions for logged-out users.
 	 *
-	 * The dynamic portion of the hook name, `$_REQUEST['action']`,
-	 * refers to the name of the Ajax action callback being fired.
+	 * The dynamic portion of the hook name, `$action`, refers
+	 * to the name of the Ajax action callback being fired.
 	 *
 	 * @since 2.8.0
 	 */
-	do_action( 'wp_ajax_nopriv_' . $_REQUEST['action'] );
+	do_action( "wp_ajax_nopriv_{$action}" );
 }
 // Default status
 wp_die( '0' );