The video tutorial explores QT5 widgets, focusing on their role in user interface development. It covers the default widgets available in QT5 and introduces the concept of creating a custom painting application. The tutorial explains the QPaintDevice class and its significance in painting operations, and demonstrates how to create custom QWidgets by overriding paint events to handle user input. The video concludes with a summary and a preview of the next tutorial on creating QT5 widgets.

What are some default Q widgets included in QT5?

Describe the relationship between Q widget and Q Paint device.