The repo contains multiple docker files built around the “portal” container concept. Most of these containers contain development (tool-chains, simulators, etc). Portal Containers Concept: The idea behind portal containers is to keep the target program and all its dependencies separated from the rest of the system while allowing it to interact with files on the host. To accomplish this, the container is launched in interactive mode and a folder on the host (the portal) is volume mapped into the container. This allows any files already in the portal folder on the host system, along with any files copied to it from either the host or the container, to be accessible on both systems. This means you can, for example, run your text editor on the host system while building with a tool-chain that lives in the container.