How does it work?

Binding Attribute

 /// <summary>
 /// Place this on an attribute to note that it's a binding attribute.
 /// An extension should then claim this and bind it.
 /// </summary>
 [AttributeUsage(AttributeTargets.Class)]
 public sealed class BindingAttribute : Attribute
 {
 }

IExtensionConfigprovider interface

/// <summary>
/// Defines an interface enabling 3rd party extensions to participate 
/// in the <see cref="JobHost"/> configuration process to register 
/// their own extension types. Any registered 
/// <see cref="IExtensionConfigProvider"/> instances added to the 
/// service container will be invoked at the right time during startup.
/// </summary>
public interface IExtensionConfigProvider
{
	/// <summary>
	/// Initializes the extension. Initialization should register any extension bindings
	/// with the <see cref="IExtensionRegistry"/> instance, which can be obtained from the
	/// <see cref="JobHostConfiguration"/> which is an <see cref="System.IServiceProvider"/>.
	/// </summary>
	/// <param name="context">The <see cref="ExtensionConfigContext"/></param>
	void Initialize(ExtensionConfigContext context);
}