Relationship between Docker and CasaOS on ZimaBoard when shipped

What is the relationship between CasaOS and Docker on the ZimaBoard when it’s shipped?
Docker info command is showing zero containers / images in use. It is showing an OS of Debian which i think is the CasaOS.
Can you please give an explanation of the interoperability and arhitecture of CasaOS, Docker, Debian GNU and a running docker image.

Please let me know.
A

casaos@CasaOS:~$ sudo docker info
Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Docker Buildx (Docker Inc., v0.7.1-docker)
  scan: Docker Scan (Docker Inc., v0.12.0)

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 20.10.12
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runtime.v1.linux runc io.containerd.runc.v2
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 7b11cfaabd73bb80907dd23182b9347b4245eb5d
 runc version: v1.0.2-0-g52b36a2
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: default
  cgroupns
 Kernel Version: 5.10.0-10-amd64
 Operating System: Debian GNU/Linux 11 (bullseye)
 OSType: linux
 Architecture: x86_64
 CPUs: 4
 Total Memory: 7.619GiB
 Name: CasaOS
 ID: CTBZ:QBFX:UJTF:LAKI:ZIHA:XOKF:3N2A:WNHM:GE7I:BM3V:XAFY:773Q
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Yes, debian is the operating system, CasaOS is just a software system on debian, you can understand it as an application, and CasaOS can operate docker to do certain visualizations like installing and uninstalling.