Is there an existing issue for this?

• I have searched the existing issues

What's missing?

I've searched the available magento developer documentation regarding attribute input types.
Specifically I'm looking for developer docs illustrating how to create a custom attribute input type in code,
that can be used as the renderer for (also in code) custom entity attributes.

For example, how to extend Magento_Ui/js/dynamic-rows to create a new custom attribute input type with custom rendering.