Make the usage report description only visible to those who have permission to see the usage reports. Currently it shows to everyone regardless of permission.

In report/myfeedback/usage/index.php move (line 16):

echo "<div class=\"usagereport\"><p>" . get_string('overview_text_usage', 'report_myfeedback') . "</p>";

to below (line 21):

if ($report->get_dashboard_capability($USER->id, 'report/myfeedback:usage')) {