Where does your data team document the why they built something the way they built it?

If we look at the product domain, there are lots of artefacts to help us document the why we are building software features.

Im a great fan of the Information Product Canvas as a way to document the why we are building Information Products (but I am of course biased on that one)

Chatting with Will Turner and we hit onto the subject of where do data teams document why they made certain decisions.

If they picked Dimensional over Data Vault, where do the document why they chose that option.

If they decide to virtualise the Consumption layer rather than physicalise it, where do they document that decision.

There are 100 and 1 decision data teams make everyday, some big and some small.

When they leave how do the new team members find and understand the context of what was built and more importantly why it was built that way.

I remember in the old days when I was consulting as an architect I would use a decison document to outline the options I had, the context I used and the decision I made. It was a form of why.

How does your data team document their why?

Why did they build that thing that specificity way and not another way?