Clarification on Sample Repository Structure

/writing/structure/ の Sample Repository セクションから始め、setup.py、requirements.txt、Pipfile、virtualenv、context.py、Makefile に関する周辺のガイダンスを読みます。記載されているプロジェクト構成とワークフローを比較し、そのうえで、どの説明やリンクに明確化が必要かを特定します。セクションが推奨事項、代替案、および名前が挙げられている各ファイルの役割を一貫して説明していれば完了です。

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?