Index: wp-admin/includes/ms.php
===================================================================
--- wp-admin/includes/ms.php	(revision 35868)
+++ wp-admin/includes/ms.php	(working copy)
@@ -1074,7 +1074,7 @@
 	</table>
 	<?php
 	/** This action is documented in wp-admin/users.php */
-	do_action( 'delete_user_form', $current_user );
+	do_action( 'delete_user_form', $current_user, $allusers );
 
 	if ( 1 == count( $users ) ) : ?>
 		<p><?php _e( 'Once you hit &#8220;Confirm Deletion&#8221;, the user will be permanently removed.' ); ?></p>
Index: wp-admin/users.php
===================================================================
--- wp-admin/users.php	(revision 35868)
+++ wp-admin/users.php	(working copy)
@@ -283,8 +283,9 @@
 	 * @since 4.0.0
 	 *
 	 * @param WP_User $current_user WP_User object for the user being deleted.
+	 * @param array $userids Array of IDs for users being deleted.
 	 */
-	do_action( 'delete_user_form', $current_user );
+	do_action( 'delete_user_form', $current_user, $userids );
 	?>
 	<input type="hidden" name="action" value="dodelete" />
 	<?php submit_button( __('Confirm Deletion'), 'primary' ); ?>