core-bundle/src/Resources/contao/library/Contao/StringUtil.php
public static function prepareSlug($strSlug)
	{
		$strSlug = static::stripInsertTags($strSlug);
		$strSlug = static::restoreBasicEntities($strSlug);
		$strSlug = static::decodeEntities($strSlug);

		return $strSlug;
	}
public static function prepareSlug($strSlug)
	{
		$strSlug = static::stripInsertTags($strSlug);
		$strSlug = static::restoreBasicEntities($strSlug);
		$strSlug = static::decodeEntities($strSlug);

		return $strSlug;
	}
Prepare a slug

@param string $strSlug The slug

@return string