This release does not have a Play Store Description, so we grabbed one from version 5.1.59:

Samsung devices include technology (SE for Android) to help secure your device.
This technology uses a set of updatable policy files designed to help protect your device data.
As new threats are detected, Samsung updates the security policies on the device to prevent these new attacks.
This feature is always enabled and allows your device to be protected after a threat is detected, instead of waiting for the next scheduled software upgrade.

Installing this update ensures that you have up-to-date protections for your device.
For more on SE for Android or for tips on securing your device, please visit www.samsungknox.com/products/knox-workspace/how-to/lock-down-android.