Clarification on Sample Repository Structure

In Structuring Your Project (/writing/structure/) the section Sample Repository is a little confusing (at least for me).

1. Stating that this is the way Kenneth Reitz recommends structuring a project is a little confusing. Is there another way? (I'm sure there are) If so, is Reitz's way the de facto standard or is there another standard out there? (Perhaps links to some other popular structures would be helpful)
2. On the same vein as 1 above, in most areas the guide is opinionated but in this section by stating its the way Reitz does it, it becomes very unopinionated and this sticks out. Does this mean that the authors aren't agreed upon Reitz's methodology?
3. We haven't talked about setup.py up to this point in the guide. What is it? (https://stackoverflow.com/questions/1471994/what-is-setup-py)
4. Here it is suggested we use requirements.txt although earlier we are encouraged to use pipenv and its pipfile (although we are also shown how to use virtualenv directly), this is a bit confusing as there is no mention of a pipfile at all. Might be helpful to expand to include some notes on the pipfile and whether we should include both or one over the other.
5. The suggested project structure doesn't include context.py, but this seems to be as much a core part as the rest of the test files - should this be added?
6. The section on Makefile is also confusing - there is no reference to Makefile in the initial project structure; when exactly might one use this?

Inizia dalla sezione Sample Repository all’indirizzo /writing/structure/ e leggi le indicazioni circostanti su setup.py, requirements.txt, Pipfile, virtualenv, context.py e Makefile. Confronta la struttura del progetto e il workflow descritti, quindi individua quali spiegazioni o collegamenti richiedono chiarimenti. Il lavoro è terminato quando la sezione spiega in modo coerente le proprie raccomandazioni, le alternative e il ruolo di ogni file menzionato.