SBLockScreenViewController is the dedicated controller representing the lock screen, hosting an SBLockScreenView meant to be used in iOS 7 - iOS 9. In iOS 10 and later, SBDashBoardViewController takes place as the main controller, subclassing SBDashBoardPasscodeViewController for this specific purpose.
Examples
Accessing SBLockScreenViewController's SBLockScreenView (iOS 7 - 9)
SBLockScreenManager *manager = [%c(SBLockScreenManager) sharedInstance];
SBLockScreenViewController *lockScreenViewController = [manager lockScreenViewController];
SBLockScreenView *lockScreenView = [lockScreenViewController lockScreenView];
References