Missing information about accessing module properties

When implementing modules, the following questions could probably arise. They are currently not answered in the documentation, but I think they should:

1. How should module properties be accessed in general inside a module? The code example shows product.txt_processor.unwantedCharacters inside the prepare property. But txt_processor.unwantedCharacters would be also possible.
2. Does that work everywhere inside a module and all its nested items or are there any limitations? FileTagger, Artifact, ... for example.
3. Accessing modules has changed over time. I remember that we had to use ModUtils in previous versions of Qbs. Is ModUtils still necessary in some cases? If yes, when?
4. Is it possible to test product for other module dependencies that txt_processor does not directly depend on and to access those properties if present?
5. How to access module properties in JavaScript files loaded by a module?
6. Would that be different in JavaScript files loaded by a product?

I am going to contribute a patch to the docs, but I would be glad if somebody like kandeler could provide a short answer to these questions so that I don't have build upon assumptions.