This tells Smarty whether or not to cache the output of the templates.
By default this is set to 0, or disabled. If your templates generate
redundant redundant content, it is advisable to turn on caching. This
will result in significant performance gains. You can also have multiple
caches for the same template. A value of 1 or 2 enables caching. 1 tells
Smarty to use the current $cache_lifetime variable to determine if the
cache has expired. A value of 2 tells Smarty to use the cache_lifetime
value at the time the cache was generated. This way you can set the
cache_lifetime just before fetching the template to have granular
control over when that particular cache expires. See also is_cached.
If $compile_check is enabled, the cached content will be regenerated if
any of the templates or config files that are part of this cache are
changed. If $force_compile is enabled, the cached content will always be
regenerated.