I don't know about _squillions_, but numpy definitely has _requirements_, even if they're not represented as such in the python graph.

e.g.

  https://github.com/numpy/numpy/blob/main/.gitmodules (some source code requirements)
  https://github.com/numpy/numpy/tree/main/requirements (mostly build/ci/... requirements)
  ...

They're not represented, because those are build-time dependencies. Most users when they do pip install numpy or equivalent, just get the precompiled binaries and none of those get installed. And even if you compile it yourself, you still don't need those for running numpy.