Regarding the Properties - Custom Properties: the need of a requirement document

As a QA, I have reported a few bugs regarding the “Properties” window, but I need a requirement document to make a test procedure to test the window thoroughly.

I wanted to make a test procedure for the “Custom Properties” window but the documentation is minimal:

Therefore, I believe that a more specific requirement document is in need for every different functionality of the “Custom Properties” window.

So is it possible for someone to make a requirement document or tell me if there’s a better document than what i already found?