WordPress at a glance
function is not described

multisite_over_quota_message() WP 3.5.0

Displays the out of storage quota message in Multisite.

No Hooks.

Return

Nothing (null).

Usage

multisite_over_quota_message();

Code of multisite over quota message: wp-admin/includes/media.php VER 5.1.1

<?php
function multisite_over_quota_message() {
	echo '<p>' . sprintf( __( 'Sorry, you have used all of your storage quota of %s MB.' ), get_space_allowed() ) . '</p>';
}