Your Cloud Shell environment is a Docker container. By default, the container is started from a Google-maintained Docker image, but you can also specify a custom Docker image for your Cloud Shell.
ex. https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/sherlock-project/sherlock&tutorial=README.md
ref - https://github.com/sherlock-project/sherlock
origin - https://www.pipiscrew.com/?p=16118 google-cloud-shell-environment