Well, actually we plan to use the Dev Containers specification in the background.
If my understanding is correct, the specification defines a way to parameterize a container to become a Dev Container, and how to run the specific image inside.
They tend to put every required tool into a single image, but our approach is different. We try to dedicate an own container for each tool because then we gain some advantages (containers can run on different hosts, easier to change tools, better isolation). Our solution can be achieved in other ways like docker compose, but with DEM a Dev Env is more similar to a classical embedded IDE.