Translations:Optional settings/129/en
From LimeSurvey Manual
You can also add .html after the survey id in the following way:
// Use short URL
'urlManager' => array(
'urlFormat' => 'path',
'rules' => array (
'<sid:\d+>' => array('survey/index','urlSuffix'=>'.html','matchValue'=>true),
),
'showScriptName' => false,
),
For more information, check the Yii documentation.