The page is available only when the PHP plugin is enabled. The PHP plugin is not bundled with IntelliJ IDEA, but it can be installed on the Settings/Preferences | Plugins page, tab Marketplace, as described in Installing plugins from JetBrains repository.
Use this dialog to specify the delimiters to enclose Smarty tags in.
Smarty left delimiter
In this field, specify the desired opening delimiter. By default, the field shows the opening curly brace
Smarty right delimiter
In this field, specify the desired closing delimiter. By default, the field shows the closing curly brace
Use Smarty3 whitespaces policy
When this checkbox is selected, delimiters followed by whitespace will not be parsed as template tags.
The checkbox is available when Smarty 3.0 or later is used.