Exactamente como dijo Sirdarckcat:
function Who()
[...]
$context['members'][$i]['action'] = isset($url_data[$i]) ? $url_data[$i] : $txt['who_hidden'];
function determineActions($urls)
[...]
if (empty($ID_TOPIC))
$data[$k] = $txt['who_hidden'];
[...]
if (allowedTo($allowedActions[$actions['action']]))
$data[$k] = $txt['whoallow_' . $actions['action']];
else
$data[$k] = $txt['who_hidden'];
Las demas variables las asume cuando lista.