filters\HttpCache $sessionCacheLimiter

The name of the cache limiter to be set when session_cache_limiter() is called. The default value is an empty string, meaning turning off automatic sending of cache headers entirely. You may set this property to be public, private, private_no_expire, and nocache. Please refer to session_cache_limiter() for detailed explanation of these values.

If this property is null, then session_cache_limiter() will not be called. As a result, PHP will send headers according to the session.cache_limiter PHP ini setting.