Explanation
The Object Repository tree structure follows a hierarchical order that starts with the Application node, which represents the application or system that contains the UI elements to be automated. Under the Application node, there can be one or more Version nodes, which specify the version of the application or system. Each Version node can have one or more Screen nodes, which represent the different screens or windows of the application or system. Finally, each Screen node can have one or more UI Element nodes, which are the individual UI elements that can be used for automation. (UiPath Automation Developer study guide) References:
Object Repository Tree Structure
Object Repository