> If curl/wget are available, great, but often slim images 
> don't offer that.

I concur with Christian.  For the most part, the standard library aims to be a collection of resources helpful for building applications like curl and wget.  The applications themselves should live on the Python Package Index (PyPI).  Also, as Christian points out, this is a non-trivial project with a large scope.


> The urllib could provide a very simple download functionality
> (like http offers a simple server):
>
>    from urllib.request import urlopen
>    data = urlopen('https://.../install-poetry.py').read()
>    # print or save data

This is a simpler request and is within our scope; however, I not sure how it differs from the existing functionality in urllib.request.urlretrieve().  Can you clarify what extra functionality is being requested?