Greengrassv2 mqtt raw connection - messages I do not understand

I am doing some tests performing a connection using a generic mqtt client (mosquitto or paho). I can connect and send message to the AWS IoT Core and receiving them with the Mqtt Test client (WEB). I also receive a bunch of other messages that I do not understand. What is the purpose of those messages? Why I am receiving them? What are they saying?

$aws/things/MyDeviceId/shadow/name/AWSManagedGreengrassV2Deployment/get
{
  "shadowName": "AWSManagedGreengrassV2Deployment",
  "thingName": "MyDeviceId"
}

$aws/things/MyDeviceId-gci/shadow/get
{
  "thingName": "MyDeviceId-gci"
}

$aws/things/MyDeviceId/shadow/name/AWSManagedGreengrassV2Deployment/get/rejected
{
  "code": 404,
  "message": "No shadow exists with name: 'MyDeviceId~AWSManagedGreengrassV2Deployment'"
}

$aws/things/MyDeviceId-gci/shadow/get/rejected
{
  "code": 404,
  "message": "No shadow exists with name: 'MyDeviceId-gci'"
}

Thanks