public IReadOnlyList<AccessibilityNode> children { get; }

To add a new child, call AccessibilityHierarchy.AddNode or AccessibilityHierarchy.InsertNode on the hierarchy that the node belongs to, passing the node as the parent. To make an existing node a child of this node, or move a child to a different node, call AccessibilityHierarchy.MoveNode. To remove a child, call AccessibilityHierarchy.RemoveNode.