diff -r c7c34916027a -r 177826044cd9 wp/wp-admin/js/user-suggest.js
--- a/wp/wp-admin/js/user-suggest.js	Mon Oct 14 18:06:33 2019 +0200
+++ b/wp/wp-admin/js/user-suggest.js	Mon Oct 14 18:28:13 2019 +0200
@@ -1,3 +1,15 @@
+/**
+ * Suggests users in a multisite environment.
+ *
+ * For input fields where the admin can select a user based on email or
+ * username, this script shows an autocompletion menu for these inputs. Should
+ * only be used in a multisite environment. Only users in the currently active
+ * site are shown.
+ *
+ * @since 3.4.0
+ * @output wp-admin/js/user-suggest.js
+ */
+
 /* global ajaxurl, current_site_id, isRtl */
 
 (function( $ ) {
@@ -8,6 +20,28 @@
 			position.my = 'right top';
 			position.at = 'right bottom';
 		}
+
+		/**
+		 * Adds an autocomplete function to input fields marked with the class
+		 * 'wp-suggest-user'.
+		 *
+		 * A minimum of two characters is required to trigger the suggestions. The
+		 * autocompletion menu is shown at the left bottom of the input field. On
+		 * RTL installations, it is shown at the right top. Adds the class 'open' to
+		 * the input field when the autocompletion menu is shown.
+		 *
+		 * Does a backend call to retrieve the users.
+		 *
+		 * Optional data-attributes:
+		 * - data-autocomplete-type (add, search)
+		 *   The action that is going to be performed: search for existing users
+		 *   or add a new one. Default: add
+		 * - data-autocomplete-field (user_login, user_email)
+		 *   The field that is returned as the value for the suggestion.
+		 *   Default: user_login
+		 *
+		 * @see wp-admin/includes/admin-actions.php:wp_ajax_autocomplete_user()
+		 */
 		$( '.wp-suggest-user' ).each( function(){
 			var $this = $( this ),
 				autocompleteType = ( typeof $this.data( 'autocompleteType' ) !== 'undefined' ) ? $this.data( 'autocompleteType' ) : 'add',