OS: macOS High Sierra Version 10.13.2
Docker version: 17.09.1-ce, build 19e2cf6
I was following an example in a book to learn about how volumes work and came across this as well. On my version of docker, it is running from~/Library/Containers/com.docker.docker and you can run screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty to get into the shell. Then you can run ls /var/lib/docker/volumes