The subscribers are located in the Subscribers folder. We have Subscribers.Default and Subscribers.Default.BusGamma.
The role of the Subscribers is to handle the messages published by the PostBus when the command handlers are executed. After the command handlers are executed, it publishes the message in the bus and the queue is subscribed by the subscribers. Then it is processed further.
Here also, we have the BusGamma and the default subscriber. The actual logic remains with the Subscribers.Default , and Bus Gamma is specific to the NserviceBus implementation.
We should not write any business logic in the code which is generated with this BusGamma project. All the business logic that is required can be written in the Subscribers.Default.