LG QCircle API Reference
LG QCircle SDK is a software development toolkit that allows the creation of applications compatible with a QuickCircle case. LG QCircle SDK allows developers to make the best use out of UX features of the QuickCircle case.
Various clock widgets are provided on the phone by default to set as a Quick Circle clock. From the LG G4, you can also create a custom clock widget that users can set it as a Quick Circle clock.