Design Pattern with Message Dispatcher, Subscriber and publisher

I recently saw a new pattern (new to me) in an open source ASP.NET MVC 5 project that hase many Command, CommandHandler, and CommandInvoker ,MessageDispatcher, AddSubscriber,PublishEvent -with many interfaces- and I can't understand the pattern! Can you tell me what is this pattern's name and where can I learn about it? And what is its benefits please? Thanks in advance. I'm talking about this project:http://ift.tt/15x2o8G