The C++ code includes pybind11 bindings that assume numpy is loaded in the Python environment. It is listed as a dependency to run tests already, but the library is essentially useless without it (Canvas, Image, Matrix, Pixmap, Surface, and utils all use it).

See for example what happens if you don't have it:

>>> import skia
>>> skia.Surface(100, 100)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'numpy'

Rather than expect downstream projects to compensate I think the right fix is to call it out here.