How could a developer make sense of a Power BI Datamart?

I am wondering if and how I as a developer could somehow use a Power BI datamart in a meaningful way. By this, I understand that my development would have to be reusable.

I can download a classic Power BI Dataset as a file, I can fill it with other data, upload it again under a different name. I can also save it for later use. Just the way you work as a developer. Recently, there is even a way to version Power BI reports and models in a git repository.

With datamart, I have no idea how that would work. It seems to be a one way street into Power BI. I can't find a way to duplicate, backup, in any way reuse the development of a datamart like this.

Is this just the beginning? Is there more planned? Have I missed something?