API: pypi.org Reference: https://warehouse.readthedocs.io/api-reference/
List packages: https://pypi.org/simple/ (GET). Result is an HTML document whose BODY contains a bunch of links:
<a href="/simple/package-name">package-name</a>
Project info: https://pypi.org/pypi/PROJECT-NAME/json. The result is a JSON document, as you would predict, and includes download links, last update timestamps, SHA256 digests, and other useful context.