PyPI package health API: dependency-hygiene facts from the official PyPI JSON API — latest version, upload time, total releases, yank status, declared dependency count, requires-python constraint, license, summary, and weekly downloads (pypistats). Names are PEP 503-normalized (dots/underscores/hyphens equivalent). Use for auditing requirements.txt and pyproject.toml, supply-chain security checks, and version freshness agents. Cached up to 1 hour per package.