Support content in themes

I’m building a site with a custom theme that is rather complex. This site is going to be the landing page for a number of different products: foo, bar, and baz. I want docs for foo, bar, and baz to live with their own product repos, but I want to expose the docs on

My approach thus far is to have a git repo for that is the “source of truth” for what content should be used to generate the site. All the site content from foo, bar, and baz repos funnels into the repository via some automation and file structure convention to prevent collisions.

Where I’m running into issues is that also I’d like the devs for foo, bar, and baz to be able to stand up working versions of the site locally so they can iterate on their subset of the content and see the results in full. When thinking about how I’d like to do this, the notion of including content in a theme popped into my head.

I could create a " shadow site" in each of the foo, bar, and baz repos. Each shadow site would treat the the website source code as a theme, so when it stood up it would look the same. You can already override layouts and static content from a theme from inside your repository, so I’m wondering if it’s possible or would make sense to extend that to content as well.

Update: It would be great if this extended to data as well (basically, any user-provided content)