ArcGIS Pro 2.6 API Reference Guide
IExtensionConfig Interface
Members 

ArcGIS.Desktop.Framework.Contracts Namespace : IExtensionConfig Interface
Provides access to members that describe an extension.
Syntax
public interface IExtensionConfig 
Public Interface IExtensionConfig 
Remarks
If you want your extension to be exposed in the backstage's Extensions table, the extension's information needs to be specified in module's <extensionConfig> node in DAML. If your module needs to load to get the extension's information, your module needs to implement the IExtensionConfig interface.
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

IExtensionConfig Members
ArcGIS.Desktop.Framework.Contracts Namespace