“unnamed” docker containers get a random name assigned to them, e.g.:
○ → docker run -it debian:latest
root@106e6c22914a:/# exit
○ → docker container ls -a
CONTAINER ID IMAGE COMMAND CREATED STATUS NAMES
106e6c22914a debian:latest "bash" 33 seconds ago Exited (0) 29 seconds ago silly_rhodes
please allow me to present for your entertainment my favourite example of this:
If you’re curious what it did you can check its logs: docker logs -t bb928f3612cb
but it should be safe to remove; it may have been left when you aborted a rebuild.