ArcGIS Pro 2.8 API Reference Guide
IContentsProvider Interface
Members 

ArcGIS.Desktop.Core Namespace : IContentsProvider Interface
Panes must implement this interface to show their Contents in the Contents dock pane (eg a custom TOC)
Object Model
IContentsProvider InterfaceContents Class
Syntax
public interface IContentsProvider 
Public Interface IContentsProvider 
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

IContentsProvider Members
ArcGIS.Desktop.Core Namespace