The `OnSelectionChanged` method is a virtual method in the `NavMeshLinkTool` class, which is part of the editor tools for managing navigation mesh links in a scene. This method is called whenever the selection changes in the editor, allowing the tool to respond to changes in the selected objects. This can be useful for updating the tool's state or UI based on the current selection.

Override the `OnSelectionChanged` method in a derived class to implement custom behavior when the selection changes in the editor. This method does not take any parameters and does not return a value. It is typically used to update the tool's internal state or user interface based on the new selection.

public class CustomNavMeshLinkTool : NavMeshLinkTool
{
    public override void OnSelectionChanged()
    {
        // Custom logic to handle selection changes
        // For example, update UI elements or internal state
        UpdateUI();
    }

    private void UpdateUI()
    {
        // Implementation of UI update logic
    }
}