This package makes application icons and uicache work on iOS 8.3 and 8.4; it was included on your device automatically by the tool you used to jailbreak.
And now, as of version 1.1.0, this package makes application URLs work on iOS 9.0.
And now, as of version 1.2.0, this package was seemingly randomly modified to work on iOS 9.2 and iOS 9.3. These changes were shipped as part of the jailbreak. I have some vague reason to believe that these changes will cause some kind of problem on iOS 8.3, but for the life of me I can't find any record of why :/. Please contact me if you have issues? :(