OpenAPI doc for geodata?

I'd like to create another library for .NET, so I thought I'd start with something simple like the geodata API. Turns out I couldn't find the open API doc.
Is there one? Or is there another kind of documentation about that that just wasn't enough to make a repository yet? A cURL/Postman/etc example request would be enough for me, as reading python is not one of my string suits (although I have already started doing that).