What operations are performed in the main thread of program execution?

In the main thread of execution in iOS, operations related to updating the user interface (UI) are usually performed. This includes:

• Rendering and updating interface elements.
• Handling user events (taps, gestures).
• Calling UIKit methods and other UI frameworks.

It is important not to block the main thread with long-running operations (such as network requests or heavy computations) to keep the interface responsive. For such tasks, background threads or queues are used.