$group = optional_param('group', 0, PARAM_INT); // Group to display
$user = optional_param('user', 0, PARAM_INT); // User to display
-$date = optional_param('date', 0, PARAM_FILE); // Date to display - number or some string
+$date = optional_param('date', 0, PARAM_INT); // Date to display
$modname = optional_param('modname', '', PARAM_PLUGIN); // course_module->id
$modid = optional_param('modid', 0, PARAM_FILE); // number or 'site_errors'
$modaction = optional_param('modaction', '', PARAM_PATH); // an action as recorded in the logs