Default Dev Environment docker container

In your docs, you state:

The default Docker image is based on Ubuntu OS and includes Git, curl, Docker, Docker Compose, Kubernetes, Google Cloud support, Open JDK, Python, PHP, .NET SDK, Ruby, Go, Node.js, npm, yarn, and other tools.

(https://www.jetbrains.com/help/space/set-up-a-dev-evnvironment.html#using-the-default-dev-environment)

I'd like to build containers but strip out things I know won't be used, like Ruby, Google Cloud, .NET, etc.. Where can I find the Dockerfile you use to build the default image?