These are used to override or specify the security settings when $security is enabled. These are the possible settings:
PHP_HANDLING - boolean. If set to TRUE, the $php_handling setting is not checked for security.
IF_FUNCS - array. The names of permitted PHP functions in {if} statements.
INCLUDE_ANY - boolean. If set to TRUE, any template can be included from the file system, regardless of the $secure_dir list.
PHP_TAGS - boolean. If set to TRUE, {php}{/php} tags are permitted in the templates.
MODIFIER_FUNCS - array. The names of permitted PHP functions that can be used as variable modifiers.
ALLOW_CONSTANTS - boolean. If set to TRUE, constants via {$smarty.const.FOO} are allowed in the templates.